feat: add external repository credential resolver

[jholm117]

Summary

Adds an opt-in, provider-neutral HTTP adapter for resolving short-lived Git credentials in packaged server deployments.

Depends on #559. Once that PR merges, this diff will contain only the external resolver follow-up.

Closes #562

Changes

• configure the resolver endpoint, optional Authorization header, timeout, and response-size limit through environment variables
• send only the opaque provider reference and repository authorization context on each turn
• validate bounded Git credential-store responses and return redaction-safe failures without logging or persisting resolver bodies
• preserve the existing injectable in-process resolver and unconfigured rejection behavior
• document the resolver protocol and add unit coverage for refresh, authentication, cancellation, timeouts, size limits, invalid responses, and secret-safe errors

How was this tested?

• pnpm format:check
• pnpm typecheck
• pnpm lint:ci
• pnpm build
• pnpm test (Node 24)

Checklist

• I have read the contributing guidelines
• pnpm build, pnpm test, pnpm typecheck, pnpm lint:ci, and pnpm format:check pass locally
• Tests added/updated where it makes sense
• No hand-edits to generated code
• Docs / .env.example updated for the new configuration

---

Note

High Risk
Changes span private Git credential handling, external HTTP trust boundaries, and sandbox git exec during session init—security-sensitive paths where misconfiguration or resolver bugs could leak or mishandle credentials.

Overview
Sessions can optionally bind a persistent Git checkout in the sandbox via a new repository field (HTTPS URL, ref, sandbox path, read_only / read_write, optional credential_provider_ref). Checkout metadata is stored on the session; secrets are resolved each turn and are not persisted. Session create/get-or-create APIs accept repository, admission requires a configured sandbox provider, and SQLite/Postgres migrations add a repository column.

Sandbox behavior provisions the repo idempotently on init (fetch/update without wiping resumed work), applies read-only push blocking when configured, writes Git credential-store content before checkout, and TurnResourceResolver can force a sandbox when a session has a repository even if the agent disables sandbox in spec.

TrueForge server adds an optional HTTP repository credential resolver (REPOSITORY_CREDENTIAL_RESOLVER_*): per turn it POSTs provider ref plus tenant/session/user and repository context, validates bounded Git credential-store responses, and fails closed with redaction-safe errors. When unset, sessions with credential_provider_ref still reject via the existing injectable rejectUnconfiguredRepositoryCredentials path. Docs and .env.example describe the protocol.

^{Reviewed by Cursor Bugbot for commit a71e47f. Bugbot is set up for automated code reviews on this repo. Configure here.}

[changeset-bot]

🦋 Changeset detected

Latest commit: a71e47f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@truefoundry/trueforge	Minor
@truefoundry/trueforge-core	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR