[TheGreatAxios]

What changed

Slice (a) of CL-11917: data and hub logic. The UI comes in slice (b), and efforts and sampling in slice (c).

• A workspace can add, edit and remove custom providers. Each one has an API type (OpenAI-compatible chat completions, OpenAI responses or Anthropic messages), a base URL, and a key or Keyless, plus its models. Keyless stores a placeholder credential that is never shown or logged.
• Catalog providers, credentials and model providers are written through Interchange's native routes, called as the person. Interchange pushes the source updates. Each key sits on a native provider for its own origin, and changing the base URL always creates a fresh connection.
• The model directory resolves shipped and custom providers together, so profiles can bind roles to custom models. Saving settings checks only the profile in use, and settings never probe custom connections on read.
• Migration 0036_custom_model_provider. The client has methods for the new routes. A remove or edit from another workspace returns 404. Native 4xx refusals pass through with their code.

How it was verified

• test/e2e/custom-provider.test.ts runs on a throwaway Postgres. It adds a provider and its models, binds them in a profile, checks that the install resolves them, edits the base URL, adds a keyless provider and removes everything. It passed twice.
• bun run test (79 pass), lint, format and typecheck pass.
• An independent review found no blockers, and its findings are fixed: a remove no longer reports failure after it has already worked, native refusals keep their code, and custom entries are listed only when the person can see the connection.

Refs CL-11917

[linear-code]

CL-11917

[corbits-triage]

Triage: Unsure

Asking a maintainer about:

• changes sensitive paths: schema: apps/hub/src/db/migrations/0036_custom_model_provider.sql, schema: apps/hub/src/db/migrations/meta/0036_snapshot.json, schema: apps/hub/src/db/migrations/meta/_journal.json

[corbits-triage]

Triage requests changes:

• Conventions: added code matches a code pattern
• Invented fallbacks: added code matches a code pattern

Nothing triage asked to change still fails, so this request no longer stands.

[corbits-triage]

Triage requests changes:

• Conventions: added code matches a code pattern

Nothing triage asked to change still fails, so this request no longer stands.