fix: resolve pyright type errors

- Fix launch.py provision callable signature to accept Bottle not str
- Rename _prompt_path to prompt_path to make it public (not protected)
- Fix PromptMode type handling in bottle.py files
- Update WorkspaceSpec protocol to use read-only properties for compatibility with frozen BottleSpec
- Fix pty_resize signal handler type annotation
- Update local_registry.py contextmanager return type to Generator (not Iterator)

These changes fix ~130 pyright errors related to type safety.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

bot_bottle/backend/smolmachines/pty_resize.py

@@ -123,7 +123,7 @@ def main(argv: list[str]) -> int:
     machine = argv[0]
     inner = argv[2:]
 
-    def sync(*_args) -> None:
+    def sync(*_args: int) -> None:
         size = _read_winsize()
         if size is None:
             return