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>

ui/src/components/SpecCreationChat.tsx

@@ -43,7 +43,7 @@ export function SpecCreationChat({
   const [yoloEnabled, setYoloEnabled] = useState(false)
   const [pendingAttachments, setPendingAttachments] = useState<ImageAttachment[]>([])
   const messagesEndRef = useRef<HTMLDivElement>(null)
-  const inputRef = useRef<HTMLInputElement>(null)
+  const inputRef = useRef<HTMLTextAreaElement>(null)
   const fileInputRef = useRef<HTMLInputElement>(null)
 
   const {
@@ -98,6 +98,10 @@ export function SpecCreationChat({
     sendMessage(trimmed, pendingAttachments.length > 0 ? pendingAttachments : undefined)
     setInput('')
     setPendingAttachments([]) // Clear attachments after sending
+    // Reset textarea height after sending
+    if (inputRef.current) {
+      inputRef.current.style.height = 'auto'
+    }
   }
 
   const handleKeyDown = (e: React.KeyboardEvent) => {
@@ -355,11 +359,15 @@ export function SpecCreationChat({
               <Paperclip size={18} />
             </button>
 
-            <input
+            <textarea
               ref={inputRef}
-              type="text"
               value={input}
-              onChange={(e) => setInput(e.target.value)}
+              onChange={(e) => {
+                setInput(e.target.value)
+                // Auto-resize the textarea
+                e.target.style.height = 'auto'
+                e.target.style.height = `${Math.min(e.target.scrollHeight, 200)}px`
+              }}
               onKeyDown={handleKeyDown}
               placeholder={
                 currentQuestions
@@ -368,8 +376,9 @@ export function SpecCreationChat({
                     ? 'Add a message with your image(s)...'
                     : 'Type your response... (or /exit to go to project)'
               }
-              className="neo-input flex-1"
+              className="neo-input flex-1 resize-none min-h-[46px] max-h-[200px] overflow-y-auto"
               disabled={(isLoading && !currentQuestions) || connectionStatus !== 'connected'}
+              rows={1}
             />
             <button
               onClick={handleSendMessage}
@@ -386,7 +395,7 @@ export function SpecCreationChat({
 
           {/* Help text */}
           <p className="text-xs text-[var(--color-neo-text-secondary)] mt-2">
-            Press Enter to send. Drag & drop or click <Paperclip size={12} className="inline" /> to attach images (JPEG/PNG, max 5MB).
+            Press Enter to send, Shift+Enter for new line. Drag & drop or click <Paperclip size={12} className="inline" /> to attach images (JPEG/PNG, max 5MB).
           </p>
         </div>
       )}