Transition voting: rate a blend, adapt that pair's next one

[sanylax2]

What this is

This is your own WIP, reassembled — please sanity-check the design before merging. The feature was split across two places and neither built on its own:

• unpushed local commit f7c07ca "Worktree WIP" on main — TransitionVote, Player+Voting, TransitionVoteBar, TransitionFeedback tests
• stash@{0} on feat/transition-voting — the stored properties (transitionVoteHistoryStorage, adaptationCache), TransitionSettings.simplified(level:), and the app-layer wiring

That's why Player+Voting.swift referenced three symbols declared nowhere in the repo. The halves are disjoint and compose exactly; together they build and pass. Your stash@{0} and the feat/transition-voting branch are untouched — I used stash apply, not pop, and worked on a scratch branch.

The feature

Thumbs up/down on the transition you just heard. Votes are keyed by the directional track pair (A→B rated separately from B→A — the blend isn't symmetric) and snapshot the settings that actually produced the blend, so a downvote on an already-simplified transition is distinguishable from one on your full settings. Repeated downvotes back that pair's blend off a step at a time; upvotes let it climb back.

• TransitionVote (@Model) — plain UUID references rather than SwiftData relationships, so votes survive a track being deleted and re-imported without cascade rules getting involved.
• TransitionFeedback.simplificationLevel (ContinuityCore) — pure vote-history → level math, unit-tested and Linux-portable like the rest of the policy code.
• TransitionSettings.simplified(level:) — progressively drops beatmatching, bass swap, harmonic mixing, and shortens the blend.
• Player+Voting — adaptedTransitionSettings is cached per pair, because the scheduling check runs at 20 Hz and the history lookup is a SwiftData fetch. Invalidated on a new vote and on any settings change.
• clearTransitionState drops the votable record — an aborted blend was never fully heard, so there's nothing to rate.
• RootView supplies vote history via the same hook pattern as onQueueExhausted; TransitionVoteBar appears in both the compact and sheet Now Playing layouts.

Rebase note

One conflict, resolved by keeping both sides: origin/main (#121) added pitch-settle teardown to clearTransitionState(), and this branch added vote-state teardown to the same function. Both are now there.

Testing

• ContinuityCore 175 tests pass (+7 from TransitionFeedbackTests).
• App target builds clean for the iOS 27 simulator.
• Device verification is yours — in particular whether the thumbs bar's placement and timing feel right, which I can't judge from a build.

🤖 Generated with Claude Code