CMRT 32: Add beatgrid/cue overlay for CMRT members ("Use CMRT Data" checkbox)

[Swarnadip-Kar]

Lets a CMRT member track load its canonical track's beatgrid and cues in
place of its own -- without touching its own stored data, so unchecking
the box restores exactly what was there before, and without touching the
audio file at all (Engine keeps reading the member's own file).
Toggled per-track via a library checkbox column.

This version puts the redirect inside
Track's own mutators, so every existing caller (CueControl
included) is redirected transparently with zero changes to any of them.

Changes

• New cmrt_members.use_cmrt_data column + DAO read/write methods.
• "Use CMRT Data" library checkbox column (CheckboxDelegate, same
  CASE-gated-virtual-column pattern the other CMRT columns already use).
• Track::applyCmrtOverlay()/clearCmrtOverlay(): swaps a track's own
  cues/beats for a shifted, resampled view of its canonical track's data.
  Handles cross-sample-rate transfers correctly by reprojecting every
  beat marker and cue position through seconds (the one sample-rate-
  independent common unit) rather than a raw frame-offset add.
• Write-through in createAndAddCue()/removeCue()/trySetBeats()/the
  per-Cue updated() handler, so edits made while the overlay is active
  land on the canonical track, not the local stashed copy.
• TrackDAO applies the overlay at load time (getTrackById()) and exposes
  apply/restore entry points for the checkbox's live-toggle case.
• CmrtGroupingService purges overlaying members' cached Track objects on
  canonical re-election, so a stale TrackPointer doesn't linger.

Depends on: cmrt-fixups-stem-mbclear-refresh (#46)

[coveralls]

Coverage Report for CI Build 29039378495

Coverage decreased (-0.07%) to 30.159%

Details

• Coverage decreased (-0.07%) from the base build.
• Patch coverage: 343 uncovered changes across 9 files (34 of 377 lines covered, 9.02%).
• 7 coverage regressions across 4 files.

Uncovered Changes

File	Changed	Covered	%
src/track/track.cpp	177	6	3.39%
src/library/basetracktablemodel.cpp	57	0	0.0%
src/library/dao/trackfingerprintdao.cpp	72	15	20.83%
src/library/dao/trackdao.cpp	37	8	21.62%
src/library/tabledelegates/checkboxdelegate.cpp	15	0	0.0%
src/musicbrainz/cmrtgroupingservice.cpp	6	0	0.0%
src/library/basesqltablemodel.h	5	0	0.0%
src/library/basetracktablemodel.h	2	0	0.0%
src/library/librarytablemodel.cpp	6	5	83.33%

Coverage Regressions

7 previously-covered lines in 4 files lost coverage.

File	Lines Losing Coverage	Coverage
src/library/basetracktablemodel.cpp	3	8.36%
src/library/dao/trackfingerprintdao.cpp	2	2.03%
src/musicbrainz/cmrtgroupingservice.cpp	1	0.0%
src/track/track.cpp	1	54.36%

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Coverage Stats

Relevant Lines:	117478
Covered Lines:	35430
Line Coverage:	30.16%
Coverage Strength:	58612.69 hits per line

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💛 - Coveralls