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/AgentControl.tsx

@@ -1,4 +1,5 @@
-import { Play, Pause, Square, Loader2 } from 'lucide-react'
+import { useState } from 'react'
+import { Play, Pause, Square, Loader2, Zap } from 'lucide-react'
 import {
   useStartAgent,
   useStopAgent,
@@ -10,9 +11,12 @@ import type { AgentStatus } from '../lib/types'
 interface AgentControlProps {
   projectName: string
   status: AgentStatus
+  yoloMode?: boolean  // From server status - whether currently running in YOLO mode
 }
 
-export function AgentControl({ projectName, status }: AgentControlProps) {
+export function AgentControl({ projectName, status, yoloMode = false }: AgentControlProps) {
+  const [yoloEnabled, setYoloEnabled] = useState(false)
+
   const startAgent = useStartAgent(projectName)
   const stopAgent = useStopAgent(projectName)
   const pauseAgent = usePauseAgent(projectName)
@@ -24,7 +28,7 @@ export function AgentControl({ projectName, status }: AgentControlProps) {
     pauseAgent.isPending ||
     resumeAgent.isPending
 
-  const handleStart = () => startAgent.mutate()
+  const handleStart = () => startAgent.mutate(yoloEnabled)
   const handleStop = () => stopAgent.mutate()
   const handlePause = () => pauseAgent.mutate()
   const handleResume = () => resumeAgent.mutate()
@@ -34,21 +38,43 @@ export function AgentControl({ projectName, status }: AgentControlProps) {
       {/* Status Indicator */}
       <StatusIndicator status={status} />
 
+      {/* YOLO Mode Indicator - shown when running in YOLO mode */}
+      {(status === 'running' || status === 'paused') && yoloMode && (
+        <div className="flex items-center gap-1 px-2 py-1 bg-[var(--color-neo-pending)] border-3 border-[var(--color-neo-border)]">
+          <Zap size={14} className="text-yellow-900" />
+          <span className="font-display font-bold text-xs uppercase text-yellow-900">
+            YOLO
+          </span>
+        </div>
+      )}
+
       {/* Control Buttons */}
       <div className="flex gap-1">
         {status === 'stopped' || status === 'crashed' ? (
-          <button
-            onClick={handleStart}
-            disabled={isLoading}
-            className="neo-btn neo-btn-success text-sm py-2 px-3"
-            title="Start Agent"
-          >
-            {isLoading ? (
-              <Loader2 size={18} className="animate-spin" />
-            ) : (
-              <Play size={18} />
-            )}
-          </button>
+          <>
+            {/* YOLO Toggle - only shown when stopped */}
+            <button
+              onClick={() => setYoloEnabled(!yoloEnabled)}
+              className={`neo-btn text-sm py-2 px-3 ${
+                yoloEnabled ? 'neo-btn-warning' : 'neo-btn-secondary'
+              }`}
+              title="YOLO Mode: Skip testing for rapid prototyping"
+            >
+              <Zap size={18} className={yoloEnabled ? 'text-yellow-900' : ''} />
+            </button>
+            <button
+              onClick={handleStart}
+              disabled={isLoading}
+              className="neo-btn neo-btn-success text-sm py-2 px-3"
+              title={yoloEnabled ? "Start Agent (YOLO Mode)" : "Start Agent"}
+            >
+              {isLoading ? (
+                <Loader2 size={18} className="animate-spin" />
+              ) : (
+                <Play size={18} />
+              )}
+            </button>
+          </>
         ) : status === 'running' ? (
           <>
             <button