screenshotService.ts, videoFrameExtractor.ts, videoFrameInjector.ts,
and streamingEncoder.ts existed solely to re-export symbols from
@hyperframes/engine. No internal consumer imported from them except
index.ts → videoFrameInjector, which now imports directly from engine.

The pool (455 LOC) and worker (127 LOC) were built speculatively for
pipelining Chrome screenshots with PNG decode/blit but were never
wired into any capture path. Zero non-test source files imported them.

Also removed the esbuild entry point from producer/build.mjs, the
tsup entry point + alpha-blit alias from cli/tsup.config.ts, and
the PNG worker bootstrap from cli/src/cli.ts.

Replace 4 inline padStart(6) template literals with shared helpers:
- formatCaptureFrameName(index, ext): zero-based, for internal capture
- formatExportFrameName(index, ext): zero-based input, one-based output
  for user-facing png-sequence export

Move fullStacking.map() from inside the per-layer iteration to before
the loop, computing the element ID list once per frame instead of once
per DOM layer per frame.

…erns

- Extract seekInjectAndQueryStacking() and seekAndInject() helpers to
  deduplicate the seek+inject+query pattern across sequential loop,
  hybrid loop, and per-scene transition capture (3 call sites → 1 helper)
- Fix sceneBuf as Buffer casts by properly typing the scene-capture
  arrays as [Buffer, Set<string>][] instead of using as const + cast
- Replace as NonNullable<> cast on outputFormat with as const fallback
- Add explanatory comments on inherent linkedom DOM casts

- Replace magic 0.001/0.999 with TRANSFORM_IDENTITY_EPSILON and
  OPAQUE_ALPHA_THRESHOLD; replace BPP=6 with RGB48_BYTES_PER_PIXEL
- Add AffineMatrix tuple type + isAffineMatrix guard, eliminating
  all 4 non-null assertions on matrix indices
- Extract resolveBlitOpacity() to replace 5 identical ternaries
- Narrow fallow-ignore-file to line-level complexity suppressions