Stage 4: guided Player for both Modes and the Session summary

- buildSegments lays a Plan out as holds with Transitions (get ready,
  switch sides, next round, next exercise) or sets with count-up Rests;
  Supersets alternate members and rest per round unless asked otherwise
- SessionRunner drives segments against an injected clock: auto-advance
  with a chime, pause, skip, back, rep sets confirmed with logged reps
  and kg, timed sets started on demand, early end
- Player screen: countdown ring, accent pulse in the last 3 s, Flip
  Animation, next-up cards, Rest Screen, mute toggle, screen kept on
- Sessions table (schema v2 migration) keeps a Plan snapshot and Set
  Logs; nothing is saved when no hold or set was done
- Summary with time, exercises or sets logged, and every Set Log
- Synthesised quiet cue sounds (tools/sounds), status bar per Mode

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

GLOSSARY.md

@@ -55,14 +55,16 @@ In Workout Mode, the screen after "Set done": a count-up timer ("Resting 1:12")
 button. Nothing counts down. Timed sets start only when the user taps Start.
 
 **Transition**:
-In Stretching Mode, a short card between rounds, sides ("Switch sides") and Exercises, after which the
-next hold starts automatically. Length set per Plan, 5 s by default.
+In Stretching Mode, a short card before the first hold ("Get ready") and between rounds, sides
+("Switch sides") and Exercises, after which the next hold starts automatically. Its length is the
+Plan's "pause between holds", 5 s by default; 0 s means no Transitions.
 
 ## Sessions
 
 **Session**:
 One run-through of a Plan in the Player. It stores a snapshot of the Plan, so later edits to the Plan
-never change it. A Session is **complete** or **incomplete** (ended early).
+never change it. A Session is **complete** (reached the end) or **incomplete** (ended early). A Session
+in which no hold or set was actually done is not saved at all.
 _Avoid_: Workout, run
 
 **Player**: