v2.0.0-beta: write tools, pending-changes queue, inference loop, API routes

Phase 2 of v2.0. BooCoder is now a functional write-capable chatbot.

Write-path guard: resolveWritePath() uses resolve() (no realpath — files may
not exist for creates) + prefix-check + secret-file deny list (.env, *.pem,
id_rsa*, etc.). 23 unit tests cover traversal attacks.

Pending-changes service: queueEdit/Create/Delete → applyOne/All →
rejectOne/All → rewindOne. Edit diffs stored as JSON {old, new}. All writes
queue before touching disk; apply re-validates the path guard.

5 write tools: edit_file, create_file, delete_file, apply_pending, rewind.
Registered alongside 25 read-only tools from BooChat (30 total, alpha-sorted).
Write tools use a module-level inference context for sql+sessionId injection.

Inference loop via workspace dependency: apps/coder imports
createInferenceRunner, createBroker, ALL_TOOLS from @boocode/server (dist/).
apps/server gains declaration: true + exports map with typed subpath entries.
No code duplication — one inference engine shared by both apps.

API routes: POST /api/sessions/:id/messages (user msg → inference), POST stop,
GET/POST pending-changes CRUD (5 endpoints), WebSocket session streaming.

Dockerfile updated to build apps/server first (coder depends on its .d.ts).
Health endpoint reports tool count: {"ok":true,"db":true,"tools":30}.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/coder/src/services/tools/inference_context.ts

@@ -0,0 +1,36 @@
+import type { Sql } from '../../db.js';
+
+/**
+ * Module-level inference context for write tools.
+ *
+ * Set via `setInferenceContext()` before each inference run starts.
+ * Write tools read it via `getInferenceContext()` during execute.
+ * Same pattern as BooChat's `loadConfig()` singleton — tools need
+ * ambient state that can't be threaded through the tool-phase execute
+ * signature (which is `execute(input, projectRoot, extraRoots?)`).
+ */
+
+export interface InferenceContext {
+  sql: Sql;
+  sessionId: string;
+  taskId: string | null;
+}
+
+let current: InferenceContext | null = null;
+
+export function setInferenceContext(ctx: InferenceContext): void {
+  current = ctx;
+}
+
+export function clearInferenceContext(): void {
+  current = null;
+}
+
+export function getInferenceContext(): InferenceContext {
+  if (!current) {
+    throw new Error(
+      'Write tool called outside inference context — setInferenceContext() was not called before this run',
+    );
+  }
+  return current;
+}