fix(desktop): return typed non-500 for expected Sentry poll states (#9139)

[kodjima33]

Bug (#9139)

desktop-backend returns repeated 500s on POST /v1/webhooks/sentry/poll in prod (24x/2h), masking real failures.

Root cause

poll_sentry_feedback returns a blanket StatusCode::INTERNAL_SERVER_ERROR whenever the Sentry API call is non-2xx, the request fails, or the body doesn't parse. Prod logs show the actual state is a persistent 403 Forbidden from Sentry on every ~5-min poll (the SENTRY_AUTH_TOKEN lacks permission), so every poll emits a 500 even though nothing in this service is broken:

Sentry poll: fetching recent feedback issues
Sentry poll: found 122 existing sentry_feedback action items ...
Sentry poll: API returned 403 Forbidden        <- returned 500 to caller

Fix

Classify expected external states — auth expiry/permission (401/403), rate limit (429), upstream 5xx, network unreachable, and unparseable body — as a typed 2xx "skipped" response with a compact warn log instead of a 500. The success path is unchanged. Genuine server misconfiguration (missing SENTRY_ADMIN_UID/SENTRY_AUTH_TOKEN) still returns 500.

Response shape mirrors the success body so callers can treat ok/skipped uniformly:

{ "status": "skipped", "reason": "sentry_auth_error", "sentry_status": 403, "created": 0, "skipped": 0, "total_fetched": 0 }

Note (separate ops action)

The underlying 403 is an ops issue — SENTRY_AUTH_TOKEN for org mediar-n5 needs re-permissioning/rotation. This PR only stops the error-log noise; polling stays a no-op until the token is fixed.

Verification

• cargo test — 2 new hermetic regression tests pass (sentry_poll_skip_reason_classifies_expected_states, sentry_poll_skipped_body_is_typed_non_500_shape)
• cargo build clean, rustfmt applied

🤖 automated by hourly watchdog; opened for review, not merged.

[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}

[Git-on-my-level]

Reviewed the Sentry poll fix for #9139 — this looks clean and well-targeted.

What it does
Converts the blanket 500 returned by POST /v1/webhooks/sentry/poll on expected external states (auth/permission 401-403, rate-limit 429, upstream 5xx, network unreachable, unparseable body) into a typed 2xx {"status":"skipped", ...} response. Genuine server misconfiguration (missing SENTRY_ADMIN_UID / SENTRY_AUTH_TOKEN) still returns 500, which is the right call.

Strengths

• The "skipped" body mirrors the success body shape (status/created/skipped/total_fetched), so callers can treat ok/skipped uniformly — good design.
• Downgrades error! → warn! for transient external states, which directly addresses the prod error-log spam without hiding real failures.
• sentry_poll_skip_reason keeps the classification in one place and is covered by a focused regression test.
• Single-file, +82/-12, coherent scope around one outcome.

Verification

• Ran the two new hermetic unit tests (sentry_poll_skip_reason_classifies_expected_states, sentry_poll_skipped_body_is_typed_non_500_shape) in a clean Rust 1.88 build — both pass.
• CI (rust, lint, Swift build) is green.

Minor note (non-blocking)
sentry_unreachable and sentry_bad_response are returned directly for network/parse failures and aren't routed through sentry_poll_skip_reason (which only maps HTTP status codes). That's consistent since those reasons don't correspond to an HTTP status, just flagging in case you want them consolidated later.

Net: solid fix for the log-noise issue. Holding off on formal approval per review process; a maintainer should be good to merge if they agree with the error-vs-skipped boundary. cc @kodjima33