feat: add multiple terminal tabs with rename capability

Add support for multiple terminal instances per project with tabbed
navigation in the debug panel. Each terminal maintains its own PTY
session and WebSocket connection.

Backend changes:
- Add terminal metadata storage (id, name, created_at) per project
- Update terminal_manager.py with create, list, rename, delete functions
- Extend WebSocket endpoint to /api/terminal/ws/{project}/{terminal_id}
- Add REST endpoints for terminal CRUD operations
- Implement deferred PTY start with initial resize message

Frontend changes:
- Create TerminalTabs component with neobrutalism styling
- Support double-click rename and right-click context menu
- Fix terminal switching issues with transform-based hiding
- Use isActiveRef to prevent stale closure bugs in connect()
- Add double requestAnimationFrame for reliable activation timing
- Implement proper dimension validation in fitTerminal()

Other updates:
- Add GLM model configuration documentation to README
- Simplify client.py by removing CLI_COMMAND support
- Update chat session services with consistent patterns

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.env.example

@@ -1,13 +1,6 @@
 # Optional: N8N webhook for progress notifications
 # PROGRESS_N8N_WEBHOOK_URL=https://your-n8n-instance.com/webhook/...
 
-# CLI Command Selection
-# Choose which CLI command to use for the agent.
-# - claude: Uses Anthropic's official Claude Code CLI (default)
-# - glm: Uses GLM CLI (or any other compatible CLI)
-# Defaults to 'claude' if not specified
-# CLI_COMMAND=claude
-
 # Playwright Browser Mode
 # Controls whether Playwright runs Chrome in headless mode (no visible browser window).
 # - true: Browser runs in background, invisible (recommended for using PC while agent works)