feat: capture_work — braindump → decomposed issues → filed in gitea (P4)

The last big agent capability. In the Capture screen, a rough braindump runs real
big-model decomposition into a small, estimated issue set; you review/edit the
labels and approve, and the issues are opened in gitea. This is the one place the
big model earns its keep (docs/agent-tools.md).

core (@commitea/core):
- capture-work: PROPOSE_ISSUES_TOOL + CAPTURE_SYSTEM; captureWork(complete, dump)
  forces a single structured decomposition and returns validated issues; parseCaptureArgs
  drops blank titles + invalid est/p labels. ProposedIssue / CaptureProposal.
- gitea client: createIssue({title, body?, labelIds?}) → POST /issues, normalized.

app:
- model bridge model:capture runs captureWork on the (loaded) big model.
- gitea bridge gitea:createIssues opens each approved issue with its est/* + p/*
  labels (reusing the #41 label-id resolver — zero-pollution, no invented labels).
- Capture screen: when a model is configured, "Brew tickets" runs real capture and
  "Approve all" files the set; otherwise the scripted demo interview runs. Fixed a
  race — the brew handler re-checks model status at click time so a configured
  model never falls into the scripted path before status resolves.

Verified: 108 core tests green (7 capture + createIssue added), desktop typecheck
clean, 14 fixture e2e green. Gated live e2e against gemma-4-26b: the auth braindump
→ 3 real tickets ("Resolve token refresh + session staleness" est/3d p/1, "Fix
webhook double-firing" est/2d p/2, "Write auth setup docs" est/1d p/3), reviewable
and editable; Discard so the test files nothing (createIssue POST is unit-tested).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/desktop/src/main/model.ts

@@ -9,6 +9,7 @@
 
 import {
   buildProjectView,
+  captureWork,
   type ChangeProposal,
   type ChatMessage,
   createChatClient,
@@ -120,4 +121,19 @@ export function registerModelIpc(): void {
       return { ok: false as const, reason: 'error' as const, message: e instanceof Error ? e.message : String(e) }
     }
   })
+
+  // capture_work — braindump → proposed issue set. The big model does the
+  // decomposition (with one loaded local model, that's the loaded one). Returns
+  // a proposal; nothing is filed until the Capture tray approves it.
+  ipcMain.handle('model:capture', async (_event, braindump: string) => {
+    if (!router) return { ok: false as const, reason: 'unconfigured' as const }
+    const model = await resolveLoadedModel(router.big.baseUrl, router.big.model)
+    const chat = createChatClient({ ...router.big, model }, fetch)
+    try {
+      const proposal = await captureWork((m, t) => chat.complete(m, t), braindump)
+      return { ok: true as const, ...proposal }
+    } catch (e) {
+      return { ok: false as const, reason: 'error' as const, message: e instanceof Error ? e.message : String(e) }
+    }
+  })
 }