feat: Add YOLO mode for rapid prototyping without browser testing

Add a new YOLO (You Only Live Once) mode that skips all browser testing
and regression tests for faster feature iteration during prototyping.

Changes made:

**Core YOLO Mode Implementation:**
- Add --yolo CLI flag to autonomous_agent_demo.py
- Update agent.py to accept yolo_mode parameter and select appropriate prompt
- Modify client.py to conditionally include Playwright MCP server (excluded in YOLO mode)
- Add coding_prompt_yolo.template.md with static analysis only verification
- Add get_coding_prompt_yolo() to prompts.py

**Server/API Updates:**
- Add AgentStartRequest schema with yolo_mode field
- Update AgentStatus to include yolo_mode
- Modify process_manager.py to pass --yolo flag to subprocess
- Update agent router to accept yolo_mode in start request

**UI Updates:**
- Add YOLO toggle button (lightning bolt icon) in AgentControl
- Show YOLO mode indicator when agent is running in YOLO mode
- Add useAgentStatus hook to track current mode
- Update startAgent API to accept yoloMode parameter
- Add YOLO toggle in SpecCreationChat completion flow

**Spec Creation Improvements:**
- Fix create-spec.md to properly replace [FEATURE_COUNT] placeholder
- Add REQUIRED FEATURE COUNT section to initializer_prompt.template.md
- Fix spec_chat_session.py to create security settings file for Claude SDK
- Delete app_spec.txt before spec creation to allow fresh creation

**Documentation:**
- Add YOLO mode section to CLAUDE.md with usage examples
- Add checkpoint.md slash command for creating detailed commits

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

server/routers/agent.py

@@ -11,7 +11,7 @@ from pathlib import Path
 
 from fastapi import APIRouter, HTTPException
 
-from ..schemas import AgentStatus, AgentActionResponse
+from ..schemas import AgentStatus, AgentActionResponse, AgentStartRequest
 from ..services.process_manager import get_manager
 
 
@@ -68,15 +68,19 @@ async def get_agent_status(project_name: str):
         status=manager.status,
         pid=manager.pid,
         started_at=manager.started_at,
+        yolo_mode=manager.yolo_mode,
     )
 
 
 @router.post("/start", response_model=AgentActionResponse)
-async def start_agent(project_name: str):
+async def start_agent(
+    project_name: str,
+    request: AgentStartRequest = AgentStartRequest(),
+):
     """Start the agent for a project."""
     manager = get_project_manager(project_name)
 
-    success, message = await manager.start()
+    success, message = await manager.start(yolo_mode=request.yolo_mode)
 
     return AgentActionResponse(
         success=success,