feat(workspace,smart-scroll): per-conversation cwd + LSP view; smart auto-scroll

workspace ([email protected]): a cwd field in the Model sidebar view (GET/PUT /conversations/:id/cwd) + a new 'Language Servers' view (GET /conversations/:id/lsp) with per-server connected/starting/error badges, spinner, error text, and refresh. Store-owned reactive cwd, re-seeded on focus change; works for DRAFTS too (targets the draft's client-minted id, which survives promotion, so turn 1 runs in the chosen cwd). Network seam normalizes the untyped LSP body.

smart-scroll: pure stick-to-bottom reducer + injected controller shell (scroll/scrollend + a ResizeObserver on the content so the view follows async height changes — markdown/highlight, images, collapses, viewport reflow), plus a floating scroll-to-bottom button. FIX: restore the transcript scrollbar — the refactor moved overflow-y-auto to an inner child, so the flex-1 container needed min-h-0 to constrain instead of growing to content.

harness: vitest-setup polyfills Element.scrollTo + ResizeObserver (jsdom implements neither), fixing App component tests. docs: backend-handoff pruned (CR-3 resolved/removed); added cwd/LSP verification courier (backend confirmed all 6 asks ✅); removed the resolved cache-warming-timer courier.

Verified: svelte-check 0 errors, biome clean, 523 tests pass, vite build OK.

1 files changed, 0 insertions, 80 deletions

diff --git a/backend-handoff-cache-warming-timer.md b/backend-handoff-cache-warming-timer.md
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-# FE → backend handoff — cache-warming: next-warm timestamp + manual-warm timer reset
-
-> **Courier doc** (dispatch-web → arch-rewrite, carried by the user). `lsp` does not span the repos.
-> **From:** dispatch-web orchestrator · **To:** arch-rewrite orchestrator · **Courier:** the user.
-> Focused ask split out of `backend-handoff.md` CR-3. Two requests, both ADDITIVE / backward-compatible.
-
-## Why
-The FE shipped a Cache Warming view: enabled toggle, minutes+seconds interval, a **live countdown to
-the next warm**, a manual **Warm now** button, and a **history** of each warm's hit %. Two of those —
-the countdown and a reliably-fresh "last cache %" — can't be done accurately from what the wire
-exposes today. The FE currently fakes them best-effort (countdown anchored to the last warm the FE
-*observed* + interval; manual warm % taken from the HTTP response because the surface doesn't refresh).
-We'd like to make them authoritative.
-
-## What I found in the backend (so these asks are precise, not guesses)
-Read of `packages/cache-warming/src/warmer.ts` + `packages/transport-http/src/app.ts`:
-
-1. **`POST /chat/warm` bypasses the warmer.** The handler (`transport-http/src/app.ts:240–289`) calls
-   `warmService.warm(conversationId, …)` **directly**. It never goes through `CacheWarmer`, so a manual
-   warm does NOT: re-arm the automatic timer, update the warmer's `lastPct`, or call `onSurfaceChange()`.
-   ⇒ the cache-warming **surface does not refresh** after a manual warm (no `update` pushed), and the
-   automatic timer keeps counting from the *previous* warm — a manual warm doesn't reset the cycle.
-2. **No next-warm time is tracked.** `armTimer` (`warmer.ts:99`) arms a relative
-   `timers.setTimer(fn, state.intervalMs)` but stores no absolute fire time, and `ConversationState`
-   (`warmer.ts:61`) is `{ enabled, intervalMs, active, lastPct, token }`. There is nothing the surface
-   could carry to tell a client *when* the next warm fires.
-
-## Ask 1 — serve a machine-readable next-warm (and last-warm) timestamp on the surface
-Record the absolute fire time when the timer is armed and expose it (plus the last warm's time) on the
-**conversation-scoped `cache-warming` surface**, pushed on every change via the existing
-`onSurfaceChange()` (warm completes, toggle, interval change, turn start/settle).
-
-- `nextWarmAt`: epoch-ms the next automatic warm is scheduled to fire, or `null` when not scheduled
-  (disabled, or `active` i.e. a turn is generating so the timer is cancelled).
-- `lastWarmAt`: epoch-ms of the most recent completed warm, or `null` if none yet.
-
-**Suggested shape — no `@dispatch/ui-contract` bump needed:** add ONE `custom` field to the spec
-(the escape hatch already exists; non-supporting clients gracefully skip it):
-```ts
-{
-  kind: "custom",
-  rendererId: "cache-warming-timer",
-  payload: {
-    nextWarmAt: number | null,   // epoch-ms, or null when not scheduled
-    lastWarmAt: number | null,   // epoch-ms, or null when never warmed
-  },
-}
-```
-(If you'd rather not add a field, a `stat` carrying an ISO/epoch string works too, but a machine-
-readable `custom` payload is cleanest for the countdown — the FE needs the number, not a display
-string.) The FE will read this in its cache-warming feature and render an exact countdown; it already
-parses the surface fields itself, so wiring a `cache-warming-timer` renderer is a small FE change.
-
-## Ask 2 — reset the automatic timer on a manual warm (and refresh the surface)
-Confirm or change: a manual `POST /chat/warm` should be treated as "a warm just happened" for that
-conversation, i.e. route it through (or notify) the `CacheWarmer` so it:
-1. **re-arms the automatic timer** from *now* (the countdown restarts at the full interval), and
-2. **updates `lastPct`** from the manual warm's result and **calls `onSurfaceChange()`** so subscribers
-   get an `update` (this also fixes the surface "last cache %" not refreshing after a manual warm).
-
-Per the source, none of this happens today (Ask-1 finding #1). The minimal change is a
-`CacheWarmer.warmNow(conversationId)` that does what the automatic `fireWarm` already does — warm →
-set `lastPct` → `onSurfaceChange()` → `armTimer()` — and have the `/chat/warm` handler call THAT
-instead of `warmService.warm` directly. (If you intend manual warms to be a *separate*, non-cycle-
-resetting probe, tell us and we'll keep the FE's manual entry purely local — but the user's intent is
-that a manual warm resets the cycle.)
-
-## What the FE does once this lands
-- Drop the FE's best-effort countdown anchor and use `nextWarmAt` directly → exact, drift-free
-  countdown that also reflects generation pauses (null while `active`).
-- Render history from the authoritative surface signal (using `lastWarmAt` changes), removing the
-  FE-side de-dup/identical-pct workaround noted in `reports/cache-warming-feature.md`.
-
-## References
-- Backend: `packages/cache-warming/src/warmer.ts`, `packages/transport-http/src/app.ts:240`,
-  `packages/cache-warming/src/pure.ts` (surface spec builder), the cache-warming surface
-  (`id:"cache-warming"`, region `"side"`, conversation-scoped).
-- FE: `src/features/cache-warming/` (view-model + view), `backend-handoff.md` CR-3 (superseded by this
-  doc), the original `frontend-cache-warming-handoff.md`.
-- No contract version bump required if Ask 1 uses the `custom` escape hatch; Ask 2 is server-internal.