fix(data-api): widen accounts-summary route's statement_timeout to 10s

[JSONbored]

Summary

• Confirmed live in production (pg_stat_activity + Postgres container logs) that GET /api/v1/accounts/:ss58 was still tripping canceling statement due to statement timeout after fix(postgres): correct account_events index shape + safety-scan wording #8154's index fix — the query plan is correct now (no Sort, both new indexes used), but the route's two sequential hotkey/coldkey scans across account_events' 87 chunks still occasionally exceed the dispatcher's shared 3000ms default under real concurrent load.
• The sibling /api/v1/accounts/:ss58/events route hit this exact class of problem first and already carries its own SET LOCAL statement_timeout = '10000ms' override rather than raising the global default for every other, lighter route. Ports that same override to the summary route.

Test plan

• npx vitest run tests/data-api.test.ts — 543/543 pass (4 tests updated for the new SET LOCAL call in the mock queue)
• npx tsc --noEmit — clean (pre-existing unrelated codegen errors only)
• npx tsx scripts/scan-public-safety.ts — passed
• npx prettier --check — clean

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.82%. Comparing base (88a3cf9) to head (67be041).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8155   +/-   ##
=======================================
  Coverage   97.82%   97.82%           
=======================================
  Files         415      415           
  Lines       28892    28893    +1     
  Branches    10850    10850           
=======================================
+ Hits        28264    28265    +1     
  Misses        141      141           
  Partials      487      487           

Files with missing lines	Coverage Δ
workers/data-api.ts	98.00% <100.00%> (+<0.01%)	⬆️

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