CLI: add a 'castle tool' lens + sweep for model alignment

The tools lens coding assistants need. 'castle tool list [--json]' lists tools
(programs with a manager:path deployment) surfacing each tool's actual EXECUTABLE
— resolved from pyproject [project.scripts], which can differ from the program
name (litellm-intent-router → intent-router) — plus description and install state.
'castle tool info <name> [--json]' details one; 'castle tool install|uninstall'.
--json is a clean machine-readable catalog for building context.

Sweep: main.py descriptions/help mention the tool lens; 'frontend'→'static' in
install help; add.py._detect drops the dead behavior return (add adopts source
only); stale comments/help fixed. Docs (CLAUDE.md/README/registry) document
'castle tool'. Tests: cli/tests/test_tool.py (list/info/json).

Suites: core 124, cli 29, castle-api 58.

docs/registry.md

@@ -195,7 +195,7 @@ system_dependencies: [pandoc, poppler-utils]
 ```
 
 System packages that must be installed for the program to work. Displayed
-in `castle list --kind tool` and the dashboard.
+in `castle tool list` / `castle tool info` and the dashboard.
 
 ### `version` — Program version