Fall back from an unusable selected inference provider

[TheGreatAxios]

Summary

• When the selected default or project-local provider is missing or incomplete, resolution uses the next fully resolvable catalog provider
• Explicit --provider still fails closed
• Empty local.model is treated as unset so a healthy pick is not abandoned

Verification

• bun run typecheck, bun run build, and bun run test pass
• bun test ./src/settings.test.ts passes

Fixes CL-7545

[linear-code]

CL-7545

[TheGreatAxios]

Primary · Approve

Session-only fallback in resolveProvider. Unusable default/local walks recents then remaining catalog keys. --provider stays fail-closed. Empty local.model is unset. Malformed baseURL still fail-closes at normalize (counsel/greybeard: do not treat as unusable). Merge as it stands.

[TheGreatAxios]

Critic · Comment

No blocking findings on the contracted behavior: CLI fail-closed, no persist, local.model does not follow siblings, throw strings unchanged.

Should-fix that landed: empty local.model no longer abandons a healthy original pick.

Waived: malformed nonempty baseURL still throws from normalize instead of walking siblings — specified, not a miss.

[TheGreatAxios]

Greybeard · Comment

Approve. resolveProvider owns session-only recovery. Remaining catalog keys run only after a failed original pick, not when nothing was selected. local.model stays paired with the original provider. Do not persist the fallback as the new default.