v7.0.0

Major — recorder model cleanup. One breaking change, removing long-deprecated API.

Removed (BREAKING)

• The three deprecated abstract recorder base classes are gone:
  KeyedRecorder<T>, SequenceRecorder<T>, BoundaryStateTracker<T> (previously
  exported from footprintjs/trace and footprintjs/advanced). They were
  deprecated in v5 in favor of the composable stores and are now removed.
  Composition via KeyedStore / SequenceStore / BoundaryStateStore is the
  only recorder-storage model — there is no base class to extend.

  Migration — replace inheritance with a composed store field:

  // before (7.0.0 removed this)
  class TokenRecorder extends KeyedRecorder<TokenEntry> {
    onLLMCall(e) { this.store(e.runtimeStageId, e.usage); }
  }
  // after
  class TokenRecorder implements ScopeRecorder {
    readonly id = 'tokens';
    private readonly store = new KeyedStore<TokenEntry>();
    onLLMCall(e) { this.store.set(e.runtimeStageId, e.usage); }
    getForStep(id) { return this.store.get(id); }   // expose what you need
    clear() { this.store.clear(); }
  }

Changed

• The built-in recorders (MetricRecorder, QualityRecorder, InOutRecorder,
  CombinedNarrativeRecorder) now compose a store instead of extending a base.
  Their public query methods (getByKey / aggregate / accumulate /
  getEntries / getEntriesForStep / getEntryRanges / getEntriesUpTo / …) are
  unchanged — only the (deprecated) base-class identity is gone. instanceof KeyedRecorder / SequenceRecorder checks no longer apply.