feat: add configurable CLI command and UI improvements

Add support for alternative CLI commands via CLI_COMMAND environment
variable, allowing users to use CLIs other than 'claude' (e.g., 'glm').
This change affects all server services and the main CLI launcher.

Key changes:

- Configurable CLI command via CLI_COMMAND env var (defaults to 'claude')
- Configurable Playwright headless mode via PLAYWRIGHT_HEADLESS env var
- Pin claude-agent-sdk version to <0.2.0 for stability
- Use tail -500 for progress notes to avoid context overflow
- Add project delete functionality with confirmation dialog
- Replace single-line input with resizable textarea in spec chat
- Add coder agent configuration for code implementation tasks
- Ignore issues/ directory in git

Files modified:
- client.py: CLI command and Playwright headless configuration
- server/main.py, server/services/*: CLI command configuration
- start.py: CLI command configuration and error messages
- .env.example: Document new environment variables
- .gitignore: Ignore issues/ directory
- requirements.txt: Pin SDK version
- .claude/templates/*: Use tail -500 for progress notes
- ui/src/components/ProjectSelector.tsx: Add delete button
- ui/src/components/SpecCreationChat.tsx: Auto-resizing textarea
- ui/src/components/ConfirmDialog.tsx: New reusable dialog
- .claude/agents/coder.md: New coder agent configuration

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

server/main.py

@@ -6,10 +6,26 @@ Main entry point for the Autonomous Coding UI server.
 Provides REST API, WebSocket, and static file serving.
 """
 
+import os
 import shutil
 from contextlib import asynccontextmanager
 from pathlib import Path
 
+from dotenv import load_dotenv
+
+# Load environment variables from .env file if present
+load_dotenv()
+
+
+def get_cli_command() -> str:
+    """
+    Get the CLI command to use for the agent.
+
+    Reads from CLI_COMMAND environment variable, defaults to 'claude'.
+    This allows users to use alternative CLIs like 'glm'.
+    """
+    return os.getenv("CLI_COMMAND", "claude")
+
 from fastapi import FastAPI, HTTPException, Request, WebSocket
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import FileResponse
@@ -124,11 +140,12 @@ async def health_check():
 @app.get("/api/setup/status", response_model=SetupStatus)
 async def setup_status():
     """Check system setup status."""
-    # Check for Claude CLI
-    claude_cli = shutil.which("claude") is not None
+    # Check for CLI (configurable via CLI_COMMAND environment variable)
+    cli_command = get_cli_command()
+    claude_cli = shutil.which(cli_command) is not None
 
-    # Check for Claude CLI configuration directory
-    # Note: Claude CLI no longer stores credentials in ~/.claude/.credentials.json
+    # Check for CLI configuration directory
+    # Note: CLI no longer stores credentials in ~/.claude/.credentials.json
     # The existence of ~/.claude indicates the CLI has been configured
     claude_dir = Path.home() / ".claude"
     credentials = claude_dir.exists() and claude_dir.is_dir()