feat: Reginald is real — model router + agent loop + query_project (P4)

The fixture chat panel is now a working agent. Ask Reginald a question and it
consults the real project through a tool loop, then answers in grounded prose.
Read-only v0 — writes still go through the propose-approve controls.

core (@commitea/core/agent):
- chat-client: OpenAI-wire chat completions over an injected fetch (same seam as
  gitea). Points at any OpenAI-compatible endpoint (LM Studio/Ollama/OpenAI).
- model-router: small model for prose + the read tool; big model reserved for
  later decomposition (pickModel).
- agent-loop: runAgentTurn drives call→tool→result→call until prose (or a step
  budget), recording each tool step. Injected complete + execute → fully testable.
- query-project: the single read tool's engine — compact focus/board/calibration/
  issue/search views built from scheduler + lifecycle + calibration; unbuilt views
  return a notImplemented marker (never fabricated). The model reports, never computes.
- agent-tools: query_project declaration + Reginald's system prompt.

app:
- main model bridge (model:status, model:chat) runs the loop; query_project
  reconciles the repo and builds the view. Model traffic stays in main (token/CSP).
  gitea.ts refactored to share getGiteaClient + reconcileSnapshot.
- preload + global.d.ts expose the model bridge; useChat drives the panel — real
  agent turn when a model is configured, scripted fixture reply otherwise (so
  fixture e2e is unchanged). A subtle "consulted the project" activity line.

Model config (env, defaults to LM Studio on :1234): COMMITEA_MODEL_URL /
_SMALL (google/gemma-4-e4b) / _BIG (qwen/qwen3.6-35b-a3b). COMMITEA_E2E=1 keeps
it unconfigured so the panel stays scripted.

Verified: 88 core tests green (14 agent: client parse, loop tool/error/budget,
all views) + a gated live integration test. Desktop typecheck clean, 14 fixture
e2e green. Gated live e2e drives the real app against gitea + gemma-4-e4b: asked
"what now?", Reginald called query_project and answered "focus is on issue #2"
(the real scheduler pick).

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

apps/desktop/src/main/model.ts

@@ -0,0 +1,69 @@
+/**
+ * Main-process model bridge — Reginald's brain runs here. Model traffic (like
+ * gitea's) stays in main: the renderer is CSP-locked and never talks to the
+ * LLM directly. On `model:chat` it drives the agent loop against the configured
+ * OpenAI-compatible endpoint, executing `query_project` by reconciling the repo
+ * and building the requested view. v0 is read-only — writes still go through the
+ * propose-approve controls.
+ */
+
+import {
+  buildProjectView,
+  type ChatMessage,
+  createChatClient,
+  type ModelRouter,
+  type ProjectView,
+  type QueryFilters,
+  REGINALD_SYSTEM,
+  REGINALD_TOOLS,
+  runAgentTurn,
+} from '@commitea/core'
+import { ipcMain } from 'electron'
+
+import { getGiteaClient, reconcileSnapshot } from './gitea.js'
+
+/** Small local model for prose + the read tool; big model reserved for later decomposition. */
+function resolveModelRouter(): ModelRouter | null {
+  if (process.env.COMMITEA_E2E === '1') return null // e2e uses the scripted fixture Reginald
+  const baseUrl = process.env.COMMITEA_MODEL_URL ?? 'http://localhost:1234/v1'
+  if (!baseUrl) return null
+  return {
+    small: { baseUrl, model: process.env.COMMITEA_MODEL_SMALL ?? 'google/gemma-4-e4b' },
+    big: { baseUrl, model: process.env.COMMITEA_MODEL_BIG ?? 'qwen/qwen3.6-35b-a3b' },
+  }
+}
+
+export function registerModelIpc(): void {
+  const router = resolveModelRouter()
+
+  ipcMain.handle('model:status', () => ({
+    configured: !!router,
+    model: router?.small.model ?? null,
+  }))
+
+  ipcMain.handle('model:chat', async (_event, messages: ChatMessage[]) => {
+    if (!router) return { ok: false as const, reason: 'unconfigured' as const }
+    const client = getGiteaClient()
+    const chat = createChatClient(router.small, fetch)
+
+    const execute = async (name: string, args: unknown) => {
+      if (name !== 'query_project') return { error: `unknown tool: ${name}` }
+      if (!client) return { error: 'gitea is not configured' }
+      const snap = await reconcileSnapshot(client)
+      const a = (args ?? {}) as { view: ProjectView; filters?: QueryFilters }
+      return buildProjectView(a.view, a.filters, snap, new Date())
+    }
+
+    try {
+      const turn = await runAgentTurn({
+        complete: (m, t) => chat.complete(m, t),
+        messages: [{ role: 'system', content: REGINALD_SYSTEM }, ...messages],
+        tools: REGINALD_TOOLS,
+        execute,
+      })
+      return { ok: true as const, content: turn.content, steps: turn.steps }
+    } catch (e) {
+      return { ok: false as const, reason: 'error' as const, message: e instanceof Error ? e.message : String(e) }
+    }
+  })
+}