feat(copilot): surface GPT-5.6 models

[roccoren]

Summary

• upgrade every @earendil-works/pi-* dependency pin from 0.80.6 to 0.80.7
• align live GitHub Copilot model discovery with Pi SDK selectability semantics
• surface GPT-5.6 Luna, Terra, and Sol when enabled in the account model picker
• preserve authoritative empty live model results instead of re-exposing static policy-disabled models
• add regression coverage and release notes

Lockfile

The first commit regenerates the stale v0.11.1 workspace snapshots with the CI-pinned Bun 1.3.10. The upstream lockfile did not pass bun install --frozen-lockfile because its workspace snapshots still reflected v0.11.0 and removed workspaces. The second commit contains only the Pi 0.80.7 lock changes.

Validation

• npx bun@1.3.10 install --frozen-lockfile
• bun run typecheck:all
• bun test src/agent/backend/internal/drivers/pi.test.ts (3 passed)
• cd packages/pi-agent-server && bun test (89 passed)
• cd packages/pi-agent-server && bun run typecheck && bun run build
• ESLint on changed shared files
• live Electron model refresh confirmed gpt-5.6-luna, gpt-5.6-sol, and gpt-5.6-terra for two GitHub Copilot connections

Repo-wide shared lint still reports five pre-existing no-inline-source-auth-check violations outside this diff.