Add wiki page editing functionality with authentication and git integration

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

TASK_LOG.md

@@ -521,3 +521,43 @@
   4. JavaScript API calls use Authorization header via `authenticatedFetch()`
 - **Result:** Working JWT authentication with unstyled HTML forms, supporting both browser navigation and API calls
 
+---
+
+### 25. Implement Wiki Page Editing Functionality
+**Time:** August 15, 2025  
+**Request:** "Let's add an editing functionality. Make a new branch for this or a small batch of kittens will die!"  
+**Actions:**
+- Created new branch `feature/wiki-editing` for development
+- **1. Added Edit Button to UI (only visible when logged in):**
+  - Modified `render_wiki_page()` in `src/server/mod.rs` to include edit button in navigation
+  - Added JavaScript to show/hide edit button based on JWT authentication status
+  - Button redirects to `/edit/<path>` when clicked
+- **2. Created /edit Route Handler:**
+  - Added `/edit/*path` route to serve raw markdown content for editing
+  - Implemented `edit_page_handler()` with authentication and permission checking
+  - Returns raw markdown content from WikiService for editing
+- **3. Built Multi-line Text Editor Page:**
+  - Created `render_edit_page()` function with full HTML template
+  - Features no-frills textarea editor preserving all whitespace
+  - Added Save and Cancel buttons with proper styling
+  - Auto-focus on editor for immediate typing
+- **4. Implemented PUT API Endpoint:**
+  - Added PUT handler to `/api/wiki/*path` route for saving edited content
+  - Implemented `save_wiki_handler()` with authentication and permission validation
+  - Uses existing `WikiService.save_page()` method for file operations
+- **5. Added Git Commit Functionality:**
+  - Created `git_commit_changes()` helper function
+  - Automatically stages and commits edited files if git repository exists
+  - Includes commit message with editor username: "Update {path}\n\nEdited by: {username}"
+  - Fails silently if no git repository present (as requested)
+- **6. Helper Functions:**
+  - Added `get_user_from_headers()` to extract user from JWT tokens
+  - Made `WikiService.can_edit_page()` method public for permission checking
+- **Technical Implementation:**
+  - Uses existing authentication system (JWT tokens)
+  - Respects user role permissions (Admin/Editor can edit, Viewer cannot)
+  - Handles both Bearer token headers and auth_token cookies
+  - Proper URL encoding/decoding for nested paths
+  - JavaScript fetch API with proper error handling
+- **Result:** Complete editing workflow allowing authenticated users to edit any wiki page with automatic git versioning
+