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/preload/index.ts

@@ -11,12 +11,16 @@ const api = {
     getIssue: (index: number) => ipcRenderer.invoke('gitea:getIssue', index),
     /** Apply an estimate/priority change (the write path); resolves to the plan + fresh issue. */
     applyChange: (change: unknown) => ipcRenderer.invoke('gitea:applyChange', change),
+    /** File a set of captured issues with their est/* + p/* labels. */
+    createIssues: (issues: unknown) => ipcRenderer.invoke('gitea:createIssues', issues),
   },
   model: {
     /** Whether a model endpoint is configured (else the UI keeps the scripted Reginald). */
     status: () => ipcRenderer.invoke('model:status'),
     /** One agent turn: messages in, Reginald's prose + the tools it consulted out. */
     chat: (messages: unknown) => ipcRenderer.invoke('model:chat', messages),
+    /** Decompose a braindump into a proposed issue set (capture_work). */
+    capture: (braindump: string) => ipcRenderer.invoke('model:capture', braindump),
   },
 }