fix(frontend): show why a repository never appeared, not an empty dropdown

[pranav8764]

Problem

A repository connected through the archiatros-sre GitHub App never appeared, and the user got no indication why.

The backend was returning HTTP 500 — installation 142620052 was created under a previous GitHub App and can no longer mint a token:

"failed to generate installation token","error":"unexpected status code fetching token: 404","installation_id":142620052
ListRepositories ... error: rpc error: code = Internal desc = failed to authorize with github

The UI swallowed all of it:

Failure	What the user saw
listGitHubRepositories 500s	setRepositories([]) → an empty, enabled dropdown showing only -- Select Repository --, indistinguishable from "this installation genuinely has no repos"
listGitHubInstallations fails	.catch(… return { installations: [] }) → the "no installations" branch → an "Install App" button telling the user to do the thing they had just done
Install completes	Gateway 303s to ?github=connected, but nothing read the param and there was no polling — the repo only appeared on a later full reload

Change

lib/api.ts — fetchAPI now throws an ApiError carrying the HTTP status and the gateway's machine-readable code. It still extends Error, so the ~17 callers that only read .message are untouched; the signature is unchanged. The gateway's envelope is {"error": CODE, "message": …}, so code ?? error is read (verified over the wire). Adds describeRequestError, settle, isInstallationUsable, and repositoryConnectionHealth.

dashboard/[workspaceId]/page.tsx

• repoError / installationsError state; both silent swallows replaced with a visible role="alert" + Retry, matching the treatment ConnectedRepositories already used.
• A failed installations call can never render "Install App" — the error branch is checked before the empty branch.
• A failed config call no longer reads as "backend not configured" (same bug class, three lines away).
• Reads ?github=connected via useSearchParams, refetches once, shows a confirmation, then clears the marker. Wrapped in <Suspense> — without it next build fails the route.
• status === 'revoked' renders as "Reconnect required" with a reconnect action and is excluded from the picker. Missing/unrecognised status still reads as connected, so this degrades gracefully until the server-side status lands.
• 409 INSTALLATION_REVOKED gets plain-language copy; any other non-2xx still yields a specific error (e.g. failed to list repositories (HTTP 500 LIST_REPOS_FAILED)) rather than an empty dropdown.

dashboard/page.tsx — revoked connections show "Reconnect required" + a Reconnect link instead of a stale "Indexed" badge; leftover raw zinc/red colors migrated to theme tokens.

Bugs found and fixed during review

• Refresh silently discarded a pending repository choice while leaving the project name filled. handleCreate then skipped the attach with no error, producing a project labelled "No Repository". The choice is now preserved unless GitHub stopped offering that repository.
• Concurrent fetches could land out of order — an older snapshot could win. Both fetch paths are sequence-guarded.
• A null JSON error body threw TypeError instead of ApiError, defeating every isApiError branch.
• A ProjectCard reconnect failure was written to state that rendered nowhere.
• Submit stayed enabled while repositories were reloading, allowing a cross-installation attach.

Verification

• npm test — 26 pass (16 new). The 500 case renders the real page component and asserts the error, the Retry, and the absence of -- Select Repository --.
• npm run lint clean on changed files; npx tsc --noEmit clean; npm run build succeeds.
• Backend behaviour confirmed live: make health 8/8, the 500 reproduced in the integration-service log, and the error envelope shape confirmed over the wire.

Not yet observable in production

Three behaviours depend on sibling units and are inert until those land — by design, and the code degrades gracefully meanwhile:

• repository_connections.status is still CHECK (status IN ('connected','disabled','archived','error')) — 'revoked' needs the migration.
• Nothing writes github_installations.status yet (no installation.deleted webhook handler).
• No handler emits INSTALLATION_REVOKED yet.

Blocker (outside this repo, needs the user)

The GitHub App archiatros-sre has a Setup URL of http://localhost:8080/... but the gateway publishes on 8180. Every row in github_install_sessions still has consumed_at IS NULL, so no install has ever completed. Until that is corrected at https://github.com/settings/apps/archiatros-sre, a fresh install cannot be exercised.

🤖 Generated with Claude Code