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>

packages/core/src/agent/agent-loop.ts

@@ -0,0 +1,69 @@
+/**
+ * The agent turn loop. Given a model `complete` fn, the conversation, the tool
+ * declarations, and an `execute` that actually runs a tool, it drives the
+ * call→tool→result→call cycle until the model answers in prose (or a step
+ * budget is hit). Pure orchestration with injected I/O — the model and the tool
+ * executor are both stubbable, so the loop is fully unit-testable offline.
+ */
+
+import type { ChatMessage, CompletionResult, ToolDecl } from './chat-client.js'
+
+/** A tool the loop ran, with the raw args and its stringified result — for the UI's activity trail. */
+export interface AgentStep {
+  tool: string
+  arguments: string
+  result: string
+}
+
+export type ToolExecutor = (name: string, args: unknown) => Promise<unknown>
+
+export interface AgentTurn {
+  content: string
+  steps: AgentStep[]
+  /** The full conversation including this turn's assistant/tool messages. */
+  messages: ChatMessage[]
+}
+
+const DEFAULT_MAX_STEPS = 4
+
+function stringify(result: unknown): string {
+  return typeof result === 'string' ? result : JSON.stringify(result)
+}
+
+export async function runAgentTurn(opts: {
+  complete: (messages: ChatMessage[], tools?: ToolDecl[]) => Promise<CompletionResult>
+  messages: ChatMessage[]
+  tools: ToolDecl[]
+  execute: ToolExecutor
+  maxSteps?: number
+}): Promise<AgentTurn> {
+  const maxSteps = opts.maxSteps ?? DEFAULT_MAX_STEPS
+  const convo: ChatMessage[] = [...opts.messages]
+  const steps: AgentStep[] = []
+
+  for (let step = 0; step < maxSteps; step++) {
+    const { content, toolCalls } = await opts.complete(convo, opts.tools)
+    if (toolCalls.length === 0) {
+      convo.push({ role: 'assistant', content })
+      return { content, steps, messages: convo }
+    }
+    convo.push({ role: 'assistant', content, toolCalls })
+    for (const tc of toolCalls) {
+      let result: unknown
+      try {
+        const args = tc.arguments ? JSON.parse(tc.arguments) : {}
+        result = await opts.execute(tc.name, args)
+      } catch (e) {
+        result = { error: e instanceof Error ? e.message : String(e) }
+      }
+      const resultStr = stringify(result)
+      steps.push({ tool: tc.name, arguments: tc.arguments, result: resultStr })
+      convo.push({ role: 'tool', toolCallId: tc.id, name: tc.name, content: resultStr })
+    }
+  }
+
+  // Out of tool budget — force a final prose answer with tools withheld.
+  const final = await opts.complete(convo, [])
+  convo.push({ role: 'assistant', content: final.content })
+  return { content: final.content, steps, messages: convo }
+}