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`.

core/src/castle_core/config.py

@@ -139,8 +139,12 @@ class CastleConfig:
 
     @property
     def tools(self) -> dict[str, ProgramSpec]:
-        """Return programs that are tools (behavior == 'tool')."""
-        return {k: v for k, v in self.programs.items() if v.behavior == "tool"}
+        """Programs deployed as a PATH tool (a `runner: path` service) — derived
+        from deployments, not the `behavior` label."""
+        tool_programs = {
+            s.program or n for n, s in self.services.items() if s.run.runner == "path"
+        }
+        return {k: v for k, v in self.programs.items() if k in tool_programs}
 
     @property
     def frontends(self) -> dict[str, ProgramSpec]:

core/src/castle_core/deploy.py

@@ -614,6 +614,9 @@ def _build_run_cmd(
         case "static":
             # No process — the gateway file_servers this service's root.
             return []
+        case "path":
+            # No process — installed on PATH via `uv tool install` at enable time.
+            return []
         case _:
             raise ValueError(f"Unsupported runner: {run.runner}")  # type: ignore[union-attr]
 

core/src/castle_core/lifecycle.py

@@ -198,6 +198,8 @@ async def activate(name: str, config: CastleConfig, root: Path) -> ActionResult:
         prog, comp = _program_for(name, config)
         if comp is None:
             return ActionResult(name, "activate", "error", f"unknown program '{prog}'")
+        if _on_path(prog):  # already installed — skip the (slow) editable reinstall
+            return ActionResult(name, "activate", "ok", f"{name}: on PATH")
         return await run_action("install", prog, comp, root)
 
     if manager == "none":

core/src/castle_core/manifest.py

@@ -89,9 +89,27 @@ class RunStatic(RunBase):
     root: str = "dist"  # served dir, relative to the program source
 
 
+class RunPath(RunBase):
+    """A CLI installed on the user's PATH via ``uv tool install`` — no process.
+
+    Like ``remote``/``static`` it has no systemd unit; its manager is **PATH**.
+    The referenced program is what gets installed; its lifecycle is
+    install/uninstall (which is what start/stop/enable/disable map to).
+    """
+
+    runner: Literal["path"]
+
+
 RunSpec = Annotated[
     Union[
-        RunCommand, RunPython, RunContainer, RunNode, RunCompose, RunRemote, RunStatic
+        RunCommand,
+        RunPython,
+        RunContainer,
+        RunNode,
+        RunCompose,
+        RunRemote,
+        RunStatic,
+        RunPath,
     ],
     Field(discriminator="runner"),
 ]

core/tests/conftest.py

@@ -42,6 +42,10 @@ def castle_root(tmp_path: Path) -> Generator[Path, None, None]:
             },
         },
         "services": {
+            "test-tool": {
+                "program": "test-tool",
+                "run": {"runner": "path"},
+            },
             "test-svc": {
                 "program": "test-svc-comp",
                 "description": "Test service",

core/tests/test_lifecycle.py

@@ -34,6 +34,28 @@ class TestIsActive:
         config = load_config(castle_root)
         assert lifecycle.is_active("does-not-exist", config) is False
 
+    def test_path_service_checks_path(self, castle_root: Path) -> None:
+        # A `runner: path` service (a tool) is active when on PATH.
+        from castle_core.manifest import ProgramSpec, RunPath, ServiceSpec, manager_for
+
+        assert manager_for("path") == "path"
+        config = load_config(castle_root)
+        config.programs["mytool"] = ProgramSpec(id="mytool", source="/tmp/mytool")
+        config.services["mytool"] = ServiceSpec(program="mytool", run=RunPath(runner="path"))
+        with patch.object(lifecycle, "_on_path", return_value=True) as mock:
+            assert lifecycle.is_active("mytool", config) is True
+        mock.assert_called_once_with("mytool")
+
+    def test_remote_service_is_active(self, castle_root: Path) -> None:
+        # A remote service has no local process; the manager is `none` → available.
+        from castle_core.manifest import RunRemote, ServiceSpec
+
+        config = load_config(castle_root)
+        config.services["ext"] = ServiceSpec(
+            program="ext", run=RunRemote(runner="remote", base_url="http://x")
+        )
+        assert lifecycle.is_active("ext", config) is True
+
     def test_static_service_active_when_dist_built(self, castle_root: Path, tmp_path: Path) -> None:
         # A frontend is a `runner: static` service; active once its served dir exists.
         from castle_core.manifest import ProgramSpec, RunStatic, ServiceSpec