fix(01-review): IN-03 delete vestigial ring-buffer.test.ts breadcrumb

tests/offscreen/ring-buffer.test.ts

@@ -1,29 +0,0 @@
-// tests/offscreen/ring-buffer.test.ts — vestigial entry point.
-//
-// Under D-09..D-11 this file pinned the single-continuous-recorder ring
-// buffer (first-chunk header pin + 30 s age-trim). Those semantics are
-// retired in favour of the D-13 restart-segments architecture (debug
-// session webm-playback-freeze): each segment is a self-contained ~10 s
-// WebM with its own EBML header and seed keyframe, so a special
-// `isFirst` flag is no longer meaningful.
-//
-// The equivalent invariants under D-13 are exercised in
-// `tests/offscreen/segment-rotation.test.ts`. This file is kept as a
-// breadcrumb so a future reader grepping for "ring buffer" lands on the
-// correct successor — and so the retirement is auditable in `git log`
-// (the original 4 tests were deleted in the same commit that added the
-// segment-rotation suite).
-//
-// See: .planning/debug/webm-playback-freeze.md "Activation Plan"
-//      step 4 — the D-09..D-11 invariants are replaced, not weakened.
-
-import { describe, it, expect } from 'vitest';
-
-describe('ring buffer (retired — see segment-rotation.test.ts)', () => {
-  it('D-09..D-11 first-chunk pin is retired by D-13 restart-segments', () => {
-    // Structural assertion only: the test exists to make the retirement
-    // visible in the test report. Behavioural assertions live in
-    // segment-rotation.test.ts.
-    expect(true).toBe(true);
-  });
-});