v1.25.4

Fixed

• aichat resolve <name> now ignores helper sessions created by headless forks,
  preventing those sessions from making canonical session names ambiguous.
• Exact UUID lookup still resolves helper sessions for diagnostics and recovery.
• Helper-fork tracking uses the exact session ID reported by the client, avoiding
  accidental classification when sessions are created concurrently or no ID is
  returned.

Verification

• Added coverage for helper detection, resolver filtering, failed operations,
  missing IDs, and concurrent session creation.
• The targeted resolver and helper-session suite passes all 102 tests.

Full change: #177