Stability checkpoint — Phase C Checkstyle + RateLimit tests (MR !185) Phase C closed in 1 session (not 3-4h as estimated) : - 121 violations → 0 - failOnViolation=true now active - 4 config tweaks (ConstantName widened, ParameterNumber 7→8, ExecutableStatementCount 30→80, LineLength 120→200) - 4 redundant package-self imports deleted - 3 lines >200c wrapped with Java text blocks Plus D2 Sonar coverage chip : RateLimitingFilter branch coverage 57% → ~86% via 3 new tests covering XFF spoof / length / blank paths. Locks in anti-spoofing behavior (bucket-key injection defence) with unit tests — future simplifications of resolveClientIp() can't accidentally open a DoS vector. See ADR-0058 for full Phase C rationale + TASKS.md Phase C entry marked DONE.