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/rewind.ts

@@ -0,0 +1,71 @@
+import { z } from 'zod';
+import type { ToolDef, ToolContext } from './types.js';
+import { rewindOne } from '../pending_changes.js';
+
+const RewindInput = z.object({
+  change_id: z.string().uuid().optional(),
+  all: z.boolean().optional(),
+});
+type RewindInputT = z.infer<typeof RewindInput>;
+
+export const rewindTool: ToolDef<RewindInputT> = {
+  name: 'rewind',
+  description:
+    'Revert applied changes. Provide change_id to revert a specific change, ' +
+    'or set all=true to revert all applied changes for the session (in reverse order).',
+  inputSchema: RewindInput,
+  jsonSchema: {
+    type: 'function',
+    function: {
+      name: 'rewind',
+      description:
+        'Revert applied changes. Provide change_id to revert a specific change, ' +
+        'or set all=true to revert all applied changes for the session (in reverse order).',
+      parameters: {
+        type: 'object',
+        properties: {
+          change_id: { type: 'string', format: 'uuid', description: 'ID of a specific change to revert' },
+          all: { type: 'boolean', description: 'If true, revert all applied changes for this session' },
+        },
+        required: [],
+      },
+    },
+  },
+  async execute(input: RewindInputT, projectRoot: string, context: ToolContext): Promise<unknown> {
+    if (input.change_id) {
+      const result = await rewindOne(context.sql, input.change_id, projectRoot);
+      return {
+        results: [result],
+        message: result.success
+          ? `Reverted change ${input.change_id} (${result.operation} on ${result.file_path}).`
+          : `Failed to revert: ${result.error}`,
+      };
+    }
+
+    if (input.all) {
+      // Rewind all applied changes for this session in reverse order
+      const applied = await context.sql<{ id: string }[]>`
+        SELECT id FROM pending_changes
+        WHERE session_id = ${context.sessionId} AND status = 'applied'
+        ORDER BY created_at DESC
+      `;
+      const results = [];
+      for (const row of applied) {
+        results.push(await rewindOne(context.sql, row.id, projectRoot));
+      }
+      const succeeded = results.filter((r) => r.success).length;
+      return {
+        total: results.length,
+        succeeded,
+        failed: results.length - succeeded,
+        results,
+        message:
+          results.length === 0
+            ? 'No applied changes to revert.'
+            : `Reverted ${succeeded}/${results.length} changes.`,
+      };
+    }
+
+    return { error: 'Provide either change_id or all=true.' };
+  },
+};