feat: add "Create Spec" button and fix Windows asyncio subprocess

UI Changes:
- Add "Create Spec with AI" button in empty kanban when project has no spec
- Button opens SpecCreationChat to guide users through spec creation
- Shows in Pending column when has_spec=false and no features exist

Windows Fixes:
- Fix asyncio subprocess NotImplementedError on Windows
- Set WindowsProactorEventLoopPolicy in server/__init__.py
- Remove --reload from uvicorn (incompatible with Windows subprocess)
- Add process cleanup on startup in start_ui.bat

Spec Chat Improvements:
- Enable full tool access (remove allowed_tools restriction)
- Add "user" to setting_sources for global skills access
- Use bypassPermissions mode for auto-approval
- Add WebFetch/WebSearch auto-approve hook

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

server/__init__.py

@@ -6,3 +6,12 @@ Web UI server for the Autonomous Coding Agent.
 Provides REST API and WebSocket endpoints for project management,
 feature tracking, and agent control.
 """
+
+# Fix Windows asyncio subprocess support - MUST be before any other imports
+# that might create an event loop
+import sys
+
+if sys.platform == "win32":
+    import asyncio
+
+    asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())

server/main.py

@@ -6,11 +6,17 @@ Main entry point for the Autonomous Coding UI server.
 Provides REST API, WebSocket, and static file serving.
 """
 
+import asyncio
 import os
 import shutil
+import sys
 from contextlib import asynccontextmanager
 from pathlib import Path
 
+# Fix for Windows subprocess support in asyncio
+if sys.platform == "win32":
+    asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
+
 from dotenv import load_dotenv
 
 # Load environment variables from .env file if present

server/services/spec_chat_session.py

@@ -179,15 +179,10 @@ class SpecChatSession:
                     model=model,
                     cli_path=system_cli,
                     # System prompt loaded from CLAUDE.md via setting_sources
-                    # This avoids Windows command line length limit (~8191 chars)
-                    setting_sources=["project"],
-                    allowed_tools=[
-                        "Read",
-                        "Write",
-                        "Edit",
-                        "Glob",
-                    ],
-                    permission_mode="acceptEdits",  # Auto-approve file writes for spec creation
+                    # Include "user" for global skills and subagents from ~/.claude/
+                    setting_sources=["project", "user"],
+                    # No allowed_tools restriction - full access to all tools, skills, subagents
+                    permission_mode="bypassPermissions",  # Auto-approve all tools
                     max_turns=100,
                     cwd=str(self.project_dir.resolve()),
                     settings=str(settings_file.resolve()),