Tools as PATH deployments; demote behavior from lifecycle logic

- manifest: RunPath (runner: path) — a CLI on PATH via `uv tool install`, manager
  = path, no unit/route (like remote/static).
- lifecycle/service: a path deployment's start/stop = install/uninstall (routed
  through activate/deactivate, which skip the reinstall when already on PATH).
  `castle service start/stop <tool>` and status now dispatch by manager; status
  shows the manager tag [systemd|caddy|path|none].
- config.tools() now derives from `runner: path` services, not the behavior label.
- castle-api: the "installed" flag derives from manager==path, not behavior==tool.
- create: a python-cli stack emits a `runner: path` service.

`behavior` no longer drives any runtime logic — it survives only as a display
label + `list --behavior` filter. Verified live: html2text uninstall→reinstall
round-trip via `castle service stop/start`.

cli/tests/test_create.py

@@ -75,6 +75,8 @@ class TestCreateCommand:
         assert "my-tool2" in config.programs
         comp = config.programs["my-tool2"]
         assert comp.behavior == "tool"
+        # A tool is a PATH deployment: a `runner: path` service.
+        assert config.services["my-tool2"].run.runner == "path"
 
     def test_create_supabase_app(self, castle_root: Path, tmp_path: Path) -> None:
         """A supabase app scaffolds a Patch-shaped project registered as a static