feat: integrate base role catalog into Init Mode (#368)

Update coordinator and Init Mode prompts to reference the 20 built-in
base roles during team casting. The LLM now prefers catalog roles
(which have deep charter content) over improvising custom roles.

- coordinator.ts: buildInitModePrompt() includes base role catalog
- squad.agent.md templates: Init Mode Phase 1 step 3 matches to catalog
- Both SDK and CLI template files updated in sync

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: spboyer