chore: remove all deprecated code

- Remove createThreadCas alias (CAS is global, not per-thread)
- Remove formatSkillDoc() legacy compat shim
- Remove help command (replaced by skill)
- Remove all 13 DEPRECATED_ALIASES flat commands + printDeprecation
- Fix CAS prompts in develop roles: remove stale <THREAD_ID> param
- Update README.md to remove createThreadCas reference
- Net: -86 lines, 241 tests pass

Closes #114

README.md

@@ -48,7 +48,7 @@ uncaged-workflow run solve-issue --prompt "Fix bug #42"
 ## CLI Usage
 
 ```bash
-uncaged-workflow help              # Show all commands
+uncaged-workflow                   # Print full command usage (exits with status 1)
 uncaged-workflow workflow list     # List registered workflows
 uncaged-workflow run <name>        # Start a workflow thread
 uncaged-workflow thread list       # List all threads
@@ -56,7 +56,7 @@ uncaged-workflow thread show <id>  # Inspect a thread
 uncaged-workflow skill             # Agent-consumable reference docs
 ```
 
-See `uncaged-workflow help` for the full command reference.
+Run `uncaged-workflow` with no arguments to print usage, or `uncaged-workflow skill cli` for the full CLI skill reference.
 
 ## Development