Local-only fallback: simulate a council with Claude subagents when no provider keys are set

[EddyDavies]

Right now, with zero provider keys configured, /claude-council:ask exits
immediately with Error: No providers configured. That's correct behaviour
for the cross-vendor pitch, but it leaves Claude Code users who only have
their Claude subscription (no Gemini / OpenAI / xAI / Perplexity keys) unable
to use the plugin at all.

Suggestion

Add an opt-in "local council" mode that spawns N Claude subagents in
parallel, each pinned to a different role from config/roles.json (security
auditor, devil's advocate, simplicity champion, scalability architect, etc.)
and synthesises their responses the same way the cross-vendor flow does.

The diversity is weaker than cross-model — same priors, same training data —
but role-prompting still produces meaningfully different angles, especially
for "what am I missing" / "poke holes in this" use cases. And it lets users
try the plugin before deciding whether to wire up paid API keys.

Rough shape

• New flag, e.g. --local or auto-fallback when no provider keys exist
• Reuse the existing role presets (balanced, security-focused,
  architecture, review)
• Reuse skills/deep-execution plumbing for parallel subagent dispatch
• Synthesis step is unchanged

Why it's worth doing

• Lowers the activation cost — install and try, configure later
• Makes the roles.json work pull double duty
• Plays well with /claude-council:status showing 0/4 vendors but
  "local council available"