feat: add Help page with search, streamline copilot, misc UI fixes

Adds searchable Help/User Guide page, trims copilot tool bloat,
adds OTHER department option, and various form/layout improvements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/lib/api.ts

@@ -17,7 +17,7 @@ export const copilotApi = axios.create({
   headers: {
     'Content-Type': 'application/json',
   },
-  timeout: 120000, // 2 minute timeout for AI requests
+  timeout: 300000, // 5 minute timeout for AI requests (large tasks need multiple tool calls)
 });
 
 // Token getter function - set by AuthContext when authenticated