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>

ui/src/components/SpecCreationChat.tsx

@@ -6,7 +6,7 @@
  */
 
 import { useEffect, useRef, useState } from 'react'
-import { Send, X, CheckCircle2, AlertCircle, Wifi, WifiOff, RotateCcw, Loader2, ArrowRight } from 'lucide-react'
+import { Send, X, CheckCircle2, AlertCircle, Wifi, WifiOff, RotateCcw, Loader2, ArrowRight, Zap } from 'lucide-react'
 import { useSpecChat } from '../hooks/useSpecChat'
 import { ChatMessage } from './ChatMessage'
 import { QuestionOptions } from './QuestionOptions'
@@ -16,7 +16,7 @@ type InitializerStatus = 'idle' | 'starting' | 'error'
 
 interface SpecCreationChatProps {
   projectName: string
-  onComplete: (specPath: string) => void
+  onComplete: (specPath: string, yoloMode?: boolean) => void
   onCancel: () => void
   initializerStatus?: InitializerStatus
   initializerError?: string | null
@@ -33,6 +33,7 @@ export function SpecCreationChat({
 }: SpecCreationChatProps) {
   const [input, setInput] = useState('')
   const [error, setError] = useState<string | null>(null)
+  const [yoloEnabled, setYoloEnabled] = useState(false)
   const messagesEndRef = useRef<HTMLDivElement>(null)
   const inputRef = useRef<HTMLInputElement>(null)
 
@@ -257,7 +258,9 @@ export function SpecCreationChat({
               {initializerStatus === 'starting' ? (
                 <>
                   <Loader2 size={20} className="animate-spin" />
-                  <span className="font-bold">Starting agent...</span>
+                  <span className="font-bold">
+                    Starting agent{yoloEnabled ? ' (YOLO mode)' : ''}...
+                  </span>
                 </>
               ) : initializerStatus === 'error' ? (
                 <>
@@ -284,13 +287,28 @@ export function SpecCreationChat({
                 </button>
               )}
               {initializerStatus === 'idle' && (
-                <button
-                  onClick={() => onComplete('')}
-                  className="neo-btn neo-btn-primary"
-                >
-                  Continue to Project
-                  <ArrowRight size={16} />
-                </button>
+                <>
+                  {/* YOLO Mode Toggle */}
+                  <button
+                    onClick={() => setYoloEnabled(!yoloEnabled)}
+                    className={`neo-btn text-sm py-2 px-3 ${
+                      yoloEnabled ? 'neo-btn-warning' : 'bg-white'
+                    }`}
+                    title="YOLO Mode: Skip testing for rapid prototyping"
+                  >
+                    <Zap size={16} className={yoloEnabled ? 'text-yellow-900' : ''} />
+                    <span className={yoloEnabled ? 'text-yellow-900 font-bold' : ''}>
+                      YOLO
+                    </span>
+                  </button>
+                  <button
+                    onClick={() => onComplete('', yoloEnabled)}
+                    className="neo-btn neo-btn-primary"
+                  >
+                    Continue to Project
+                    <ArrowRight size={16} />
+                  </button>
+                </>
               )}
             </div>
           </div>