## Why
`account/read` currently reports only `type: "amazonBedrock"`, so
clients cannot distinguish a Codex-managed Bedrock API key from
credentials supplied by AWS. The app UI needs that distinction to render
the appropriate account state without duplicating provider-auth logic.
Credential-source selection belongs to the Bedrock model provider
because it already owns the precedence between managed Bedrock auth and
the external AWS credential path. This builds on #27443 and #27689.
## What changed
- Added `AmazonBedrockCredentialSource` with `codexManaged` and
`awsManaged` values.
- Included the selected credential source in
`ProviderAccount::AmazonBedrock` and the app-server `Account` response.
- Made `AmazonBedrockModelProvider::account_state()` classify the source
from its managed-auth state.
- Regenerated the app-server JSON and TypeScript schemas.
- Updated app-server account documentation and downstream TUI matches.
`codexManaged` means the provider found a managed Bedrock API key.
`awsManaged` identifies the provider's external AWS credential path; it
does not assert that the AWS credential chain has been validated.
## Testing
- Added model-provider coverage for Codex-managed precedence and
AWS-managed fallback.
- Added app-server protocol serialization coverage for both wire values.
- Added app-server integration coverage for both `account/read`
responses.
- `just test -p codex-protocol -p codex-model-provider -p
codex-app-server-protocol` (497 tests passed).
After rebasing onto #27711, the `codex-app-server` test target compiled
past the image-generation `PathUri` migration. Local linking was then
interrupted by disk exhaustion (`No space left on device`).
Celia ChenandGitHub
12aaeb7bf8