feat(tide_eda): phase-1 EDA over the corpus (tempo, collab, pairings, time)

Reusable data-scientist pass that finds the stories before any viz:
- TRUE tempo parsed from setcps (corner A), vs metadata bpm (C), with A↔C delta
  (most conflicts are exact 2× half-time/double-time notation, not errors)
- studio tempo (git-creation date) vs stage tempo (gig date) — the creep 110→126
- collab fingerprint: bpm profile + lift-distinctive samples per collaborator
  (raph outed as the fast/club one ~138bpm; nova-solo ~117)
- sample pairings: lift-ranked co-occurrence, ad-hoc 'pair <prefix>' query
- cadence (all 37 canonical gigs), sample-family split, signature idioms,
  set-staples, vocabulary growth (Dirt-Samples symlink mtime, 334-pack Jul'24 burst)
Emits eda_report.json (tidy cuts for the viz phase).