feat(lsp,cwd): LSP integration + per-conversation cwd; fix cache-warming cache bust

LSP + per-conversation CWD feature:
- new bundled `lsp` extension: hand-rolled JSON-RPC codec (framing/rpc), lazy
  one-server-per-(serverID,root), per-cwd config resolution, on-demand `lsp` tool
- `conversation-store`: getCwd/setCwd (cwdKey); `session-orchestrator` defaults a
  turn's cwd from the store
- `transport-http`: cwd + lsp status endpoints; wire types in transport-contract
- host-bin: register lsp; config wiring

Cache-warming fix (the warm read 0% on the first reheat after a message):
- warm assembled tools under a different cwd than the real turn (a reheat sends no
  cwd, and the warm service had no store fallback). The skills filter rewrites the
  cwd-sensitive `load_skill` description, so the tools block — the first bytes of
  the prompt-cache prefix — diverged and the cache missed entirely. Warm now
  resolves cwd as opts.cwd ?? conversationStore.getCwd(), mirroring handleMessage.
- capture warm sends as `provider.request` spans flagged `warm:true` (thread a
  child logger into providerOpts) so warm vs real bodies are diffable (obs §3.1).
- kernel logger: span-close now merges child-bound attrs like span-open, so a
  `warm:true` query finds the closed span (with usage/status), not just the open.

Tests: warm forwards a warm-flagged logger; warm falls back to stored cwd; logger
open/close attr consistency. Full suite green (873).

8 files changed, 306 insertions, 3 deletions

diff --git a/packages/transport-http/package.json b/packages/transport-http/package.json
index d439fe4..2a3acdd 100644
--- a/packages/transport-http/package.json
+++ b/packages/transport-http/package.json
@@ -9,6 +9,7 @@
 		"@dispatch/conversation-store": "workspace:*",
 		"@dispatch/credential-store": "workspace:*",
 		"@dispatch/kernel": "workspace:*",
+		"@dispatch/lsp": "workspace:*",
 		"@dispatch/session-orchestrator": "workspace:*",
 		"@dispatch/throughput-store": "workspace:*",
 		"@dispatch/transport-contract": "workspace:*",
diff --git a/packages/transport-http/src/app.test.ts b/packages/transport-http/src/app.test.ts
index 22b26fc..07f6777 100644
--- a/packages/transport-http/src/app.test.ts
+++ b/packages/transport-http/src/app.test.ts
@@ -13,6 +13,7 @@ import { createApp } from "./app.js";
 import type {
 	ConversationStore,
 	CredentialStore,
+	LspService,
 	SessionOrchestrator,
 	WarmService,
 } from "./seam.js";
@@ -78,6 +79,7 @@ function createFakeLogger(): Logger & { readonly records: readonly CapturedLog[]
 function createFakeConversationStore(
 	store: Map<string, StoredChunk[]> = new Map(),
 	metricsStore: Map<string, TurnMetrics[]> = new Map(),
+	cwdStore: Map<string, string> = new Map(),
 ): ConversationStore {
 	return {
 		async append() {},
@@ -93,6 +95,12 @@ function createFakeConversationStore(
 		async loadMetrics(conversationId) {
 			return metricsStore.get(conversationId) ?? [];
 		},
+		async getCwd(conversationId) {
+			return cwdStore.get(conversationId) ?? null;
+		},
+		async setCwd(conversationId, cwd) {
+			cwdStore.set(conversationId, cwd);
+		},
 	};
 }
 
@@ -169,6 +177,23 @@ function createFakeWarmService(
 	};
 }
 
+function createFakeLspService(
+	statuses: readonly {
+		readonly id: string;
+		readonly name: string;
+		readonly root: string;
+		readonly extensions: readonly string[];
+		readonly state: "connected" | "starting" | "error" | "not-started";
+		readonly error?: string;
+	}[] = [],
+): LspService {
+	return {
+		async status() {
+			return statuses;
+		},
+	};
+}
+
 const noopLogger = createFakeLogger();
 
 describe("GET /health", () => {
@@ -752,6 +777,10 @@ describe("GET /conversations/:id/metrics", () => {
 			async loadMetrics() {
 				throw new Error("storage exploded");
 			},
+			async getCwd() {
+				return null;
+			},
+			async setCwd() {},
 		};
 		const app = createApp({
 			conversationStore: brokenStore,
@@ -1031,3 +1060,154 @@ describe("throughput recording + GET /metrics/throughput", () => {
 		expect(res.status).toBe(400);
 	});
 });
+
+describe("GET /conversations/:id/cwd", () => {
+	it("returns null when unset", async () => {
+		const app = createApp({
+			conversationStore: createFakeConversationStore(),
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/cwd");
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as { conversationId: string; cwd: string | null };
+		expect(body.conversationId).toBe("conv1");
+		expect(body.cwd).toBeNull();
+	});
+});
+
+describe("PUT then GET /conversations/:id/cwd", () => {
+	it("round-trips the value", async () => {
+		const store = createFakeConversationStore();
+		const app = createApp({
+			conversationStore: store,
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			logger: noopLogger,
+		});
+
+		const putRes = await app.request("/conversations/conv1/cwd", {
+			method: "PUT",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ cwd: "/home/user/project" }),
+		});
+		expect(putRes.status).toBe(200);
+		const putBody = (await putRes.json()) as { conversationId: string; cwd: string };
+		expect(putBody.conversationId).toBe("conv1");
+		expect(putBody.cwd).toBe("/home/user/project");
+
+		const getRes = await app.request("/conversations/conv1/cwd");
+		expect(getRes.status).toBe(200);
+		const getBody = (await getRes.json()) as { conversationId: string; cwd: string | null };
+		expect(getBody.cwd).toBe("/home/user/project");
+	});
+});
+
+describe("PUT /conversations/:id/cwd", () => {
+	it("with missing cwd returns 400", async () => {
+		const app = createApp({
+			conversationStore: createFakeConversationStore(),
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/cwd", {
+			method: "PUT",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({}),
+		});
+		expect(res.status).toBe(400);
+		const body = (await res.json()) as { error: string };
+		expect(body.error).toContain("cwd");
+	});
+
+	it("with empty cwd returns 400", async () => {
+		const app = createApp({
+			conversationStore: createFakeConversationStore(),
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/cwd", {
+			method: "PUT",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ cwd: "" }),
+		});
+		expect(res.status).toBe(400);
+	});
+});
+
+describe("GET /conversations/:id/lsp", () => {
+	it("returns empty servers when cwd is unset", async () => {
+		const app = createApp({
+			conversationStore: createFakeConversationStore(),
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			lspService: createFakeLspService(),
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/lsp");
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			conversationId: string;
+			cwd: string | null;
+			servers: readonly unknown[];
+		};
+		expect(body.conversationId).toBe("conv1");
+		expect(body.cwd).toBeNull();
+		expect(body.servers).toEqual([]);
+	});
+
+	it("maps the lsp service statuses to LspServerInfo[] when cwd is set", async () => {
+		const cwdStore = new Map<string, string>([["conv1", "/home/user/project"]]);
+		const store = createFakeConversationStore(new Map(), new Map(), cwdStore);
+		const lspStatuses = [
+			{
+				id: "typescript",
+				name: "TypeScript",
+				root: "/home/user/project",
+				extensions: [".ts", ".tsx"],
+				state: "connected" as const,
+			},
+			{
+				id: "lua-lsp",
+				name: "Lua LSP",
+				root: "/home/user/project",
+				extensions: [".luau"],
+				state: "error" as const,
+				error: "spawn failed",
+			},
+		];
+		const app = createApp({
+			conversationStore: store,
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			lspService: createFakeLspService(lspStatuses),
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/lsp");
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			conversationId: string;
+			cwd: string | null;
+			servers: readonly {
+				readonly id: string;
+				readonly name: string;
+				readonly root: string;
+				readonly extensions: readonly string[];
+				readonly state: string;
+				readonly error?: string;
+			}[];
+		};
+		expect(body.conversationId).toBe("conv1");
+		expect(body.cwd).toBe("/home/user/project");
+		expect(body.servers).toHaveLength(2);
+		expect(body.servers[0]?.id).toBe("typescript");
+		expect(body.servers[0]?.state).toBe("connected");
+		expect(body.servers[0]?.error).toBeUndefined();
+		expect(body.servers[1]?.id).toBe("lua-lsp");
+		expect(body.servers[1]?.state).toBe("error");
+		expect(body.servers[1]?.error).toBe("spawn failed");
+	});
+});
diff --git a/packages/transport-http/src/app.ts b/packages/transport-http/src/app.ts
index 84c7d20..7778bad 100644
--- a/packages/transport-http/src/app.ts
+++ b/packages/transport-http/src/app.ts
@@ -2,6 +2,9 @@ import type { AgentEvent, Logger } from "@dispatch/kernel";
 import type {
 	ConversationHistoryResponse,
 	ConversationMetricsResponse,
+	CwdResponse,
+	LspServerInfo,
+	LspStatusResponse,
 	ModelsResponse,
 	ThroughputResponse,
 	WarmResponse,
@@ -21,6 +24,8 @@ import {
 import {
 	type ConversationStore,
 	type CredentialStore,
+	type LspServerStatus,
+	type LspService,
 	type SessionOrchestrator,
 	ThroughputQueryError,
 	type ThroughputStore,
@@ -32,6 +37,7 @@ export interface CreateServerOptions {
 	readonly orchestrator: SessionOrchestrator;
 	readonly credentialStore: CredentialStore;
 	readonly warmService?: WarmService;
+	readonly lspService?: LspService;
 	/** Optional — defaults to a no-op store (recording disabled, empty reports). */
 	readonly throughputStore?: ThroughputStore;
 	readonly logger?: Logger;
@@ -105,7 +111,7 @@ export function createApp(opts: CreateServerOptions): Hono {
 		"*",
 		cors({
 			origin: "*",
-			allowMethods: ["GET", "POST", "OPTIONS"],
+			allowMethods: ["GET", "POST", "PUT", "OPTIONS"],
 			allowHeaders: ["Content-Type"],
 		}),
 	);
@@ -313,5 +319,87 @@ export function createApp(opts: CreateServerOptions): Hono {
 		}
 	});
 
+	app.get("/conversations/:id/cwd", async (c) => {
+		const conversationId = c.req.param("id");
+		try {
+			const cwd = await opts.conversationStore.getCwd(conversationId);
+			log.info("conversations: cwd read", { conversationId, hasCwd: cwd !== null });
+			const body: CwdResponse = { conversationId, cwd };
+			return c.json(body, 200);
+		} catch (err) {
+			log.error("conversations: cwd read failure", { err });
+			return c.json({ error: "Failed to read conversation cwd" }, 500);
+		}
+	});
+
+	app.put("/conversations/:id/cwd", async (c) => {
+		const conversationId = c.req.param("id");
+		let body: unknown;
+		try {
+			body = await c.req.json();
+		} catch {
+			log.warn("conversations/cwd: invalid JSON body");
+			return c.json({ error: "Invalid JSON body" }, 400);
+		}
+
+		if (body === null || typeof body !== "object") {
+			return c.json({ error: "Request body must be a JSON object" }, 400);
+		}
+		const obj = body as Record<string, unknown>;
+		if (typeof obj.cwd !== "string" || obj.cwd.length === 0) {
+			return c.json({ error: "Field 'cwd' is required and must be a non-empty string" }, 400);
+		}
+
+		try {
+			await opts.conversationStore.setCwd(conversationId, obj.cwd);
+			log.info("conversations: cwd set", { conversationId });
+			const response: CwdResponse = { conversationId, cwd: obj.cwd };
+			return c.json(response, 200);
+		} catch (err) {
+			log.error("conversations: cwd set failure", { err });
+			return c.json({ error: "Failed to set conversation cwd" }, 500);
+		}
+	});
+
+	app.get("/conversations/:id/lsp", async (c) => {
+		const conversationId = c.req.param("id");
+		try {
+			const cwd = await opts.conversationStore.getCwd(conversationId);
+			if (cwd === null) {
+				log.info("conversations: lsp status read (no cwd)", { conversationId });
+				const body: LspStatusResponse = { conversationId, cwd: null, servers: [] };
+				return c.json(body, 200);
+			}
+
+			if (opts.lspService === undefined) {
+				log.warn("conversations: lsp service not available", { conversationId });
+				return c.json({ error: "LSP service not available" }, 503);
+			}
+
+			const statuses = await opts.lspService.status(cwd);
+			const servers: LspServerInfo[] = statuses.map((s: LspServerStatus) => {
+				const info: LspServerInfo = {
+					id: s.id,
+					name: s.name,
+					root: s.root,
+					extensions: s.extensions,
+					state: s.state,
+					...(s.error !== undefined ? { error: s.error } : {}),
+				};
+				return info;
+			});
+			log.info("conversations: lsp status read", {
+				conversationId,
+				cwd,
+				serverCount: servers.length,
+			});
+			const body: LspStatusResponse = { conversationId, cwd, servers };
+			return c.json(body, 200);
+		} catch (err) {
+			log.error("conversations: lsp status failure", { err });
+			return c.json({ error: "Failed to read LSP status" }, 500);
+		}
+	});
+
 	return app;
 }
diff --git a/packages/transport-http/src/extension.ts b/packages/transport-http/src/extension.ts
index 5274033..6c988a5 100644
--- a/packages/transport-http/src/extension.ts
+++ b/packages/transport-http/src/extension.ts
@@ -4,6 +4,7 @@ import {
 	cacheWarmHandle,
 	conversationStoreHandle,
 	credentialStoreHandle,
+	lspServiceHandle,
 	sessionOrchestratorHandle,
 	throughputStoreHandle,
 } from "./seam.js";
@@ -14,13 +15,21 @@ export const manifest: Manifest = {
 	version: "0.0.0",
 	apiVersion: "^0.1.0",
 	trust: "bundled",
-	dependsOn: ["conversation-store", "credential-store", "session-orchestrator", "throughput-store"],
+	dependsOn: [
+		"conversation-store",
+		"credential-store",
+		"lsp",
+		"session-orchestrator",
+		"throughput-store",
+	],
 	capabilities: { network: true },
 	contributes: {
 		routes: [
 			"/chat",
 			"/chat/warm",
 			"/conversations/:id",
+			"/conversations/:id/cwd",
+			"/conversations/:id/lsp",
 			"/health",
 			"/models",
 			"/metrics/throughput",
@@ -45,6 +54,7 @@ export function createTransportHttpExtension(): Extension & {
 			const credentialStore = host.getService(credentialStoreHandle);
 			const throughputStore = host.getService(throughputStoreHandle);
 			const warmService = host.getService(cacheWarmHandle);
+			const lspService = host.getService(lspServiceHandle);
 			const logger = host.logger;
 
 			const app = createApp({
@@ -53,6 +63,7 @@ export function createTransportHttpExtension(): Extension & {
 				credentialStore,
 				throughputStore,
 				warmService,
+				lspService,
 				logger,
 			});
 
diff --git a/packages/transport-http/src/index.ts b/packages/transport-http/src/index.ts
index 64929fc..718aaef 100644
--- a/packages/transport-http/src/index.ts
+++ b/packages/transport-http/src/index.ts
@@ -19,6 +19,7 @@ export {
 export type {
 	ConversationStore,
 	CredentialStore,
+	LspService,
 	SessionOrchestrator,
 	WarmService,
 } from "./seam.js";
@@ -26,5 +27,6 @@ export {
 	cacheWarmHandle,
 	conversationStoreHandle,
 	credentialStoreHandle,
+	lspServiceHandle,
 	sessionOrchestratorHandle,
 } from "./seam.js";
diff --git a/packages/transport-http/src/seam.ts b/packages/transport-http/src/seam.ts
index e89370e..43c9d4d 100644
--- a/packages/transport-http/src/seam.ts
+++ b/packages/transport-http/src/seam.ts
@@ -2,6 +2,8 @@ export type { ConversationStore } from "@dispatch/conversation-store";
 export { conversationStoreHandle } from "@dispatch/conversation-store";
 export type { CredentialStore } from "@dispatch/credential-store";
 export { credentialStoreHandle } from "@dispatch/credential-store";
+export type { LspServerStatus, LspService } from "@dispatch/lsp";
+export { lspServiceHandle } from "@dispatch/lsp";
 export type { SessionOrchestrator, WarmService } from "@dispatch/session-orchestrator";
 export { cacheWarmHandle, sessionOrchestratorHandle } from "@dispatch/session-orchestrator";
 export type { ThroughputStore } from "@dispatch/throughput-store";
diff --git a/packages/transport-http/src/server.bun.test.ts b/packages/transport-http/src/server.bun.test.ts
index 5b4c6aa..b43469f 100644
--- a/packages/transport-http/src/server.bun.test.ts
+++ b/packages/transport-http/src/server.bun.test.ts
@@ -2,7 +2,12 @@ import { afterEach, describe, expect, test } from "bun:test";
 import type { ConfigAccess, HostAPI, Logger } from "@dispatch/kernel";
 import { createApp } from "./app.js";
 import { createTransportHttpExtension } from "./index.js";
-import type { ConversationStore, CredentialStore, SessionOrchestrator } from "./seam.js";
+import type {
+	ConversationStore,
+	CredentialStore,
+	LspService,
+	SessionOrchestrator,
+} from "./seam.js";
 
 function fakeLogger(): Logger {
 	return {
@@ -41,6 +46,10 @@ function fakeConversationStore(): ConversationStore {
 		async loadMetrics() {
 			return [];
 		},
+		async getCwd() {
+			return null;
+		},
+		async setCwd() {},
 	};
 }
 
@@ -61,6 +70,14 @@ function fakeCredentialStore(): CredentialStore {
 	};
 }
 
+function fakeLspService(): LspService {
+	return {
+		async status() {
+			return [];
+		},
+	};
+}
+
 function fakeConfig(overrides: Record<string, unknown> = {}): ConfigAccess {
 	return {
 		get<T>(key: string): T | undefined {
@@ -76,6 +93,7 @@ const SERVICES = new Map<string, unknown>([
 	["conversation-store/store", fakeConversationStore()],
 	["session-orchestrator/orchestrator", fakeOrchestrator()],
 	["credential-store/registry", fakeCredentialStore()],
+	["lsp", fakeLspService()],
 ]);
 
 function createFakeHostAPI(configOverrides: Record<string, unknown> = {}): HostAPI {
diff --git a/packages/transport-http/tsconfig.json b/packages/transport-http/tsconfig.json
index fc29c8c..fd3f3ea 100644
--- a/packages/transport-http/tsconfig.json
+++ b/packages/transport-http/tsconfig.json
@@ -6,6 +6,7 @@
 		{ "path": "../conversation-store" },
 		{ "path": "../credential-store" },
 		{ "path": "../kernel" },
+		{ "path": "../lsp" },
 		{ "path": "../session-orchestrator" },
 		{ "path": "../throughput-store" },
 		{ "path": "../transport-contract" }