Restructure chat service, web routes, and add test suite

Split monolithic chat service into modular structure with Matrix client
support, extract web server into per-resource route modules, introduce
bootstrap/main-loop separation, and add comprehensive vitest coverage
across services, repositories, and utilities. Adds project docs and
CLAUDE.md agent instructions.

src/web/routes/config.ts

@@ -0,0 +1,61 @@
+import { Router } from 'express';
+import type { WebContext } from '../context.js';
+
+export function createConfigRouter(ctx: WebContext): Router {
+  const router = Router();
+
+  router.get('/config', (_req, res) => {
+    res.json({
+      rateLimit: ctx.runtimeConfig.rateLimit,
+      browser: { dryRun: ctx.runtimeConfig.browser.dryRun },
+    });
+  });
+
+  router.put('/config', (req, res) => {
+    try {
+      const updates = req.body;
+
+      if (updates.rateLimit) {
+        if (typeof updates.rateLimit.minDelayBetweenMessagesMs === 'number') {
+          ctx.runtimeConfig.rateLimit.minDelayBetweenMessagesMs = Math.max(
+            0,
+            updates.rateLimit.minDelayBetweenMessagesMs,
+          );
+        }
+        if (typeof updates.rateLimit.maxMessagesPerHour === 'number') {
+          ctx.runtimeConfig.rateLimit.maxMessagesPerHour = Math.max(
+            1,
+            updates.rateLimit.maxMessagesPerHour,
+          );
+        }
+        if (typeof updates.rateLimit.jitterMs === 'number') {
+          ctx.runtimeConfig.rateLimit.jitterMs = Math.max(0, updates.rateLimit.jitterMs);
+        }
+      }
+
+      if (updates.browser) {
+        if (typeof updates.browser.dryRun === 'boolean') {
+          ctx.runtimeConfig.browser.dryRun = updates.browser.dryRun;
+        }
+      }
+
+      // Mirror into the loaded config so getStats reflects new values.
+      ctx.config.rateLimit.minDelayBetweenMessagesMs = ctx.runtimeConfig.rateLimit.minDelayBetweenMessagesMs;
+      ctx.config.rateLimit.maxMessagesPerHour = ctx.runtimeConfig.rateLimit.maxMessagesPerHour;
+      ctx.config.rateLimit.jitterMs = ctx.runtimeConfig.rateLimit.jitterMs;
+      ctx.config.browser.dryRun = ctx.runtimeConfig.browser.dryRun;
+
+      ctx.getOnConfigChange()?.(ctx.runtimeConfig);
+
+      ctx.activity.push('info', 'Config updated via dashboard');
+      ctx.broadcaster.push('info', 'Configuration updated via dashboard', updates);
+
+      res.json({ success: true, config: ctx.runtimeConfig });
+    } catch (error) {
+      ctx.logger.error('Failed to update config:', error);
+      res.status(400).json({ error: String(error) });
+    }
+  });
+
+  return router;
+}