refactor(cli): split claude_bottle/cli.py into a package

One file per subcommand under claude_bottle/cli/, with shared constants
and the tty helper in _common.py and dispatch in __init__.py. The
public import (from claude_bottle.cli import main) is unchanged, so
the root cli.py entrypoint and the test suite see no surface change.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude_bottle/cli/_common.py

@@ -0,0 +1,20 @@
+"""Shared constants and tty helper for cli subcommands."""
+
+from __future__ import annotations
+
+import os
+import sys
+from pathlib import Path
+
+PROG = "cli.py"
+USER_CWD = os.getcwd()
+REPO_DIR = str(Path(__file__).resolve().parent.parent.parent)
+
+
+def read_tty_line() -> str:
+    """Mirror `IFS= read -r REPLY </dev/tty`. Falls back to stdin."""
+    try:
+        with open("/dev/tty", "r") as tty:
+            return tty.readline().rstrip("\n")
+    except OSError:
+        return sys.stdin.readline().rstrip("\n")