Improve castlog report fidelity

[lexicalunit]

Context

Castlog reported seeing games where every player xid is null and no winner is set. The root cause of the null xids is on the Convoke side (see the companion PR in commander-online), but investigating turned up three real problems on this side of the wire.

Changes

Forward the SpellBot game id to castlog. report_match sends the request body through verbatim, and the game id only ever arrives in the URL path. So castlog had no way to tell a re-report of a match it already has from a brand new match — a single game legitimately produces several reports (the automatic match-end one, a later winner finalization, the post-game modal). The id is injected into the outbound body rather than trusted from the reporter's payload, since we know it authoritatively.

Don't forward a report that lost the stale-write guard. set_metadata returned True whenever the game existed, whether or not the write applied — conflating "stored" with "accepted and ignored as stale". The endpoint then called castlog unconditionally, so a delayed or out-of-order report we had just rejected locally still got pushed to castlog. It now returns which of the three outcomes happened (APPLIED / STALE / MISSING) and the forward is skipped on STALE.

Accumulate links across reports instead of replacing them. Each writer only knows about its own trackers — Convoke reports mythic_track, SpellBot writes back castlog — so a later report that simply omits a link would drop it from the game detail page. The merge happens inside the existing conditional UPDATE so the compare-and-set stays atomic. Everything outside links is still last-write-wins.

Testing

uv run pytest -n3 — 1708 passed. Three new cases cover the stale-report forward being skipped, the game id reaching castlog, and links accumulating across reports.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (4239f37) to head (cc6c460).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #2560   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          290       290           
  Lines        23508     23558   +50     
  Branches       955       957    +2     
=========================================
+ Hits         23508     23558   +50     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.