fix: make base roles opt-in via --roles flag

[bradygaster]

Summary

Makes the built-in base roles catalog opt-in instead of always-on, restoring the beloved fictional universe casting as the default experience.

Changes

File	Change
\cli-entry.ts\	Parse --roles\ flag, pass to \
unInit()\
\init.ts\	\RunInitOptions.roles\ + .init-roles\ marker file
\commands.ts\	/init --roles\ REPL command support + help text
\coordinator.ts\	Split \�uildInitModePrompt()\ into default (universe) vs opt-in (catalog) paths
\index.ts\	Read .init-roles\ marker in \handleInitCast(), cleanup after casting
\ est/init-base-roles.test.ts\	5 tests covering prompt behavior + marker lifecycle

How it works

1. Default (\squad init): Fictional universe casting — LLM picks character names freely
2. Opt-in (\squad init --roles): Includes the base roles catalog so LLM maps agents to curated role IDs
3. Marker file .squad/.init-roles\ bridges CLI → REPL → coordinator (same pattern as .init-prompt)

Review notes

• EECOM implemented, Flight coordinated + cross-reviewed, fixed ESM
  equire()\ → \import\ bug in commands.ts
• All 5 new tests pass + 100 existing init/casting/repl tests pass
• Upgrade impact: None — new flag, no behavioral change to existing users

Closes #379

cc @spboyer — this implements the base roles opt-in for your contribution. The role catalog is now available via \squad init --roles\ instead of being the default.

[bradygaster]

Hey @spboyer 👋 — Brady asked me to loop you in! Your base roles contribution (PR #369) is now opt-in via \squad init --roles. Default init still uses the fictional universe casting experience, and when users pass --roles, your curated role catalog powers the team setup. Let us know if you have any feedback on the implementation!