Add cf tutorial and graceful Ctrl+C handling

- Add Interactive Tool Picker tutorial to web docs
- Handle SIGINT signal for clean exit on Ctrl+C
- Add KeyboardInterrupt handling in main()
- Add tutorial to Getting Started section in TOC

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/cmdforge/cli/picker.py

@@ -329,11 +329,24 @@ def main():
     """Entry point for cf command."""
     global _ui_out
     import subprocess
+    import signal
+
+    # Handle Ctrl+C gracefully
+    def handle_sigint(sig, frame):
+        # Restore cursor and exit cleanly
+        sys.stderr.write(SHOW_CURSOR)
+        sys.stderr.flush()
+        sys.exit(0)
+
+    signal.signal(signal.SIGINT, handle_sigint)
 
     # Read piped input if stdin is not a tty
     piped_input = None
     if not sys.stdin.isatty():
-        piped_input = sys.stdin.read()
+        try:
+            piped_input = sys.stdin.read()
+        except KeyboardInterrupt:
+            sys.exit(0)
 
     # Check if we have a terminal available
     if not os.path.exists('/dev/tty'):
@@ -346,6 +359,9 @@ def main():
     try:
         with TTYInput() as tty_input:
             result = run_picker(tty_input)
+    except KeyboardInterrupt:
+        _write(SHOW_CURSOR)
+        sys.exit(0)
     except OSError as e:
         print(f"cf requires a terminal: {e}", file=sys.stderr)
         sys.exit(1)