fix: update reverse_proxy.py to return correct status code for upstream request timeout

[lhoupert]

closes #211

[claude]

Claude finished @lhoupert's task in 1m 21s —— View job

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Review: reverse_proxy.py upstream timeout/connect-error handling

• Gather context (diff, files)
• Review reverse_proxy.py changes
• Review test changes
• Apply ponytail-review pass
• Post final review

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✅ No blocking issues — safe to merge.

The exception ordering is safe: httpx.ConnectTimeout is a subclass of httpx.TimeoutException, not of httpx.ConnectError, so the two except clauses are disjoint and always hit the intended branch. Tests cover both new paths with a MockTransport.

Non-blocking observations:

• src/stac_auth_proxy/handlers/reverse_proxy.py:108-111 — every other error path in this codebase returns JSONResponse({"detail": ...}, status_code=...) (see Cql2BuildFilterMiddleware.py:106, EnforceAuthMiddleware.py:108). This handler instead returns a raw-text Response, so upstream-timeout/unreachable errors have a different body shape than other proxy errors, which could surprise STAC API clients that expect JSON error bodies. Consider matching the existing convention: JSONResponse({"detail": "Upstream timed out"}, status_code=504).
• Only httpx.TimeoutException and httpx.ConnectError are caught. Other httpx.TransportError subclasses that can occur mid-request against a flaky upstream (ReadError, RemoteProtocolError, etc.) still propagate as unhandled exceptions → default 500. That may be intentional scope (matching issue Upstream timeout returns 500 instead of 504 #211), but worth confirming since it's the same class of failure (upstream instability) this PR is meant to guard against.

Fix this →

Simplify (ponytail)

Nothing to cut — the diff is a minimal try/except with two branches, no unnecessary abstraction.

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💰 Estimated review cost: $0.30 · 1m21s · 15 turns

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.68%. Comparing base (8b3d3c9) to head (64a9120).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #210      +/-   ##
==========================================
+ Coverage   89.65%   89.68%   +0.03%     
==========================================
  Files          30       30              
  Lines        1343     1348       +5     
  Branches      182      182              
==========================================
+ Hits         1204     1209       +5     
  Misses         97       97              
  Partials       42       42              

Flag	Coverage Δ
unittests	89.68% <100.00%> (+0.03%)	⬆️

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[alukach]

Good fix, thanks!