v2.54.1

v2.54.1

One more instance of the enum-keyed silent-failure class (issue #70), plus a
guard so the next one can't ship unnoticed.

Fixed

• The raw timeline.export action passed type/subtype straight to
  Timeline.Export, which needs resolved resolve.EXPORT_* enum values — a
  JSON/MCP caller can't pass a live enum, so the action silently wrote nothing
  for every caller. It now resolves friendly format names (and EXPORT_*
  constant names) via the same _timeline_export_spec resolver that
  export_timeline_checked uses, and reports the resolved
  export_type/export_subtype.
• export_timeline_checked resolved enum constants against the module global
  resolve (which can be None and silently degrade the EXPORT_* args to
  strings); it now uses get_resolve(), matching the issue-#70 lesson.

Added

• An api_truth ↔ mitigation guard test: every enum-tagged catalog entry must
  declare a mitigation (its resolver/wrapper functions), each of which must
  exist in src.server. The next raw enum passthrough — a documented symbol with
  no real resolver, or a renamed/removed resolver — now fails CI. Added a
  Timeline.Export catalog entry and wired mitigation onto the AutoSyncAudio,
  CreateSubtitlesFromAudio, and CloudProject entries.

Validation

• Full offline unit/static suite green (1238 tests; new export-resolution
  regression test + the mitigation guard).
• Live-validated against DaVinci Resolve Studio 21.0.0
  (tests/live_enum_settings_check.py, read-only): fcpxml/edl resolve to the
  live EXPORT_* enum values rather than raw strings. (No timeline mutation or
  file write is performed by the check.)