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).

1 files changed, 51 insertions, 0 deletions

diff --git a/packages/lsp/src/diagnostics.test.ts b/packages/lsp/src/diagnostics.test.ts
new file mode 100644
index 0000000..9f2b6b4
--- /dev/null
+++ b/packages/lsp/src/diagnostics.test.ts
@@ -0,0 +1,51 @@
+import { describe, expect, it } from "vitest";
+import { DiagnosticsStore } from "./diagnostics.js";
+
+describe("diagnostics", () => {
+	it("formats diagnostics with severity, location, and message", () => {
+		const store = new DiagnosticsStore();
+		store.setPushDiagnostics({
+			uri: "file:///test.ts",
+			diagnostics: [
+				{
+					range: { start: { line: 0, character: 5 }, end: { line: 0, character: 10 } },
+					severity: 1,
+					source: "typescript",
+					message: "Cannot find name 'hello'.",
+				},
+			],
+		});
+
+		const formatted = store.format("file:///test.ts");
+		expect(formatted).toContain("ERROR");
+		expect(formatted).toContain("L1:6");
+		expect(formatted).toContain("Cannot find name 'hello'.");
+		expect(formatted).toContain("[typescript]");
+	});
+
+	it("merges push and pull diagnostics with deduplication", () => {
+		const store = new DiagnosticsStore();
+		const diag = {
+			range: { start: { line: 0, character: 0 }, end: { line: 0, character: 5 } },
+			severity: 1,
+			message: "Error",
+		};
+
+		store.setPushDiagnostics({
+			uri: "file:///test.ts",
+			diagnostics: [diag],
+		});
+		store.setPullDiagnostics("file:///test.ts", {
+			kind: "full",
+			items: [diag],
+		});
+
+		const merged = store.getMerged("file:///test.ts");
+		expect(merged).toHaveLength(1);
+	});
+
+	it("returns empty string when no diagnostics exist", () => {
+		const store = new DiagnosticsStore();
+		expect(store.format("file:///nonexistent.ts")).toBe("");
+	});
+});