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, 113 insertions, 0 deletions

diff --git a/notes/lsp-design.md b/notes/lsp-design.md
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+# LSP integration — design + plan
+
+> Orchestrator-authored plan (notes/ is orchestrator-editable). Drives the
+> `prompts/<unit>.md` TASK blocks. Status: AWAITING USER SIGN-OFF on the
+> decisions in §6 before summoning.
+
+## 1. Goal
+
+A **general-purpose, config-driven LSP** (Language Server Protocol) integration that
+is trivial to set up for any project, exposed to the agent as a tool and to the
+frontend as status. Hard requirements:
+
+- **MUST work for this repo** (`arch-rewrite`, TypeScript) — zero/low config.
+- **MUST work for the Roblox project** (`/home/tradam/projects/roblox`, Luau via
+  `luau-lsp`), including the bug opencode got wrong (§2).
+- Frontend endpoint: is the LSP connected, and which servers are loaded **per tab**
+  (per conversation).
+- **Per-conversation CWD**: persist it, expose get/set to the frontend (this does
+  not exist yet — cwd is currently per-turn only).
+- Frontend **handoff** document.
+
+## 2. The bug we must NOT reproduce (root cause, confirmed)
+
+opencode's `client/registerCapability` handler ignores every registration except
+`textDocument/diagnostic` (`references/opencode/.../lsp/client.ts:198-206` does
+`continue` for anything else). It *declares* `workspace.didChangeWatchedFiles.
+dynamicRegistration: true` (client.ts:249-251) but never honors the server's
+watcher registration and never runs a real filesystem watcher. So when `luau-lsp`
+registers a watch for `sourcemap.json` / `**/*.luau`, opencode silently drops it.
+Disk changes never reach the server → stale sourcemap → `TypeError: Unknown
+require` for any file created mid-session. (Confirmed against
+`/home/tradam/projects/roblox/LUA_TOOLING.md:61-66`.)
+
+**Our fix (spec-compliant, general — fixes sourcemap-style staleness for ANY
+server):**
+1. Declare `workspace.didChangeWatchedFiles.dynamicRegistration: true`.
+2. **Honor** `client/registerCapability` / `unregisterCapability` for
+   `workspace/didChangeWatchedFiles`: store the registered `watchers` (globPattern
+   + kind).
+3. Run a **real filesystem watcher** over the workspace root; on create/change/
+   delete matching a registered glob, send a `workspace/didChangeWatchedFiles`
+   notification with the correct `FileChangeType`.
+4. Keep derived files fresh: optional per-server **`watch` sidecar command** (for
+   Roblox: `rojo sourcemap <project> --watch -o sourcemap.json`). The Roblox docs
+   only avoided `--watch` *because* opencode couldn't consume the updates — once
+   (1-3) work, the sidecar + watcher close the loop with zero edits to the Roblox
+   project.
+
+## 3. Architecture (synthesized from old-dispatch + opencode references)
+
+- **JSON-RPC over stdio**, LSP `Content-Length` framing. Lazy-spawn one server
+  process per `(serverID, workspaceRoot)`; dedup concurrent spawns; track `broken`
+  servers (no retry storm). Initialize handshake (45s timeout) → `initialized` →
+  `workspace/didChangeConfiguration`.
+- **Diagnostics:** push (`textDocument/publishDiagnostics`) + pull
+  (`textDocument/diagnostic`), merged + deduped. `touchFile → didOpen/didChange →
+  waitForDiagnostics`.
+- **Server registry / matching:** by file extension + workspace-root markers.
+  Workspace root = the conversation's cwd (or nearest root-marker ancestor up to
+  cwd). Spawn cwd = workspace root.
+- **Pure core / injected shell** (constitution): the protocol codec (framing,
+  request/response correlation, capability-registration state machine, diagnostic
+  merge) is a **pure module** tested with an injected in-memory duplex stream — no
+  real child process, zero internal mocks. The edges (spawn child process, fs
+  watcher, read file) are injected adapters.
+- **Lifecycle/cleanup:** the extension owns its manager; child processes MUST be
+  killed on shutdown (no leaked LSP/sidecar procs — cf. the bracket-trick scar
+  tissue). Needs the host to call `deactivate()` on shutdown (verify; CR to
+  host-bin if missing).
+
+## 4. Units & waves (one owner per unit; single-writer)
+
+**Wave 1 (parallel — disjoint packages, kernel-only deps):**
+- **`conversation-store`** (existing, owner-summon): add per-conversation **cwd**
+  persistence to its contract + impl + tests (`getCwd`/`setCwd`, separate key
+  space). Exposes the typed surface session-orchestrator + transport-http consume.
+- **`lsp`** (NEW extension): the whole LSP client/manager/registry/file-watcher/
+  config-resolver + the model-facing `lsp` tool + a typed `lspServiceHandle`
+  (`status(root)`, `diagnostics(...)`). Depends only on kernel contracts (uses
+  `ctx.cwd`) + reads a per-cwd config file. The big unit.
+- **`transport-contract`** (existing, types-only): add `CwdResponse`/`SetCwdRequest`
+  and `LspStatusResponse` (per-tab loaded servers + connected status).
+
+**Wave 2 (parallel — depend on wave 1):**
+- **`transport-http`**: `GET`/`PUT /conversations/:id/cwd` (persist via
+  conversation-store) + `GET /conversations/:id/lsp` (resolve conversationId→cwd→
+  `lspServiceHandle.status(root)`).
+- **`session-orchestrator`**: when `/chat` omits cwd, default to the persisted
+  per-conversation cwd (load from conversation-store); persist cwd when provided.
+
+**Wave 3 (composition):**
+- **`host-bin`**: register `lsp` in `CORE_EXTENSIONS`; wire shutdown so LSP/sidecar
+  procs are killed (deactivate). Orchestrator does the build wiring (root tsconfig
+  ref for `packages/lsp`, `bun install`, any new dep, devDep
+  `typescript-language-server` for live verification).
+
+**Wave 4 (orchestrator):** full-graph typecheck/test/check; live-verify against
+this repo (TS) + Roblox (luau-lsp); write the FE handoff.
+
+## 5. Config & how each target works
+
+- **This repo (zero config):** built-in `typescript` server definition (root
+  markers `tsconfig.json`/`package.json`; command `typescript-language-server
+  --stdio`), matched on `.ts`/`.tsx`.
+- **Roblox (its existing config, ideally zero new setup):** read
+  `<cwd>/.dispatch/lsp.json` if present, else fall back to `<cwd>/opencode.json`'s
+  `lsp` key (the Roblox project already has it). When a server's
+  `initialization.luau-lsp.sourcemap.autogenerate === true` with a
+  `rojoProjectFile`, auto-spawn the `rojo sourcemap --watch` sidecar (the §2 fix).
+
+## 6. DECISIONS FOR THE USER (boundary/granularity/scope — ORCHESTRATOR §5.2)
+
+See the chat message accompanying this doc.