feat(media-use): color grading — grade/lut resolve, smart-grade, grade-compare + compare (#2041)

* feat(media-use): color grading — grade/lut resolve, smart-grade, grade-compare CLI

Add color grading to media-use as first-class resolve types plus a faithful
comparison command. All local, offline, deterministic — no model, no GPU.

- resolve -t grade / -t lut: produce a data-color-grading block (or a frozen
  .cube). Look cascade: core preset (no file) -> bundled .cube library ->
  parametric buildCube. Emitted .cube is Rec.709 and validated against core's
  colorLuts constraints (LUT_3D_SIZE <= 64) before it is frozen.
- smart grade (grade --for <media>): ffmpeg signalstats -> adjust suggestion
  (exposure / contrast / white balance), surfaced with the measured evidence on
  stderr as a starting point; never auto-applied.
- hyperframes grade-compare: renders N candidate grades onto a reference frame
  through the real runtime shader into one labeled comparison PNG, so an agent
  picks a look without opening Studio. Prepends an "original" baseline cell by
  default (--no-baseline to omit). Shares the headless-capture pipeline with
  snapshot via capture/captureCompositionFrame.
- media-use SKILL: proactive "media opportunity pass" guidance (grounded
  signal -> offer, ask once, surface don't mutate).

Verified: media-use 116/116, grade-compare 7/7, snapshot 9/9, lint + format
clean, full build green, comparison renders end to end.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* test(cli): narrow grade-compare baseline assertion off unknown-typed grading

Assert the whole cell via toEqual instead of reaching into .grading.preset /
.grading.lut on the unknown-typed field, keeping the test typecheck-clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* feat(media-use): agent-authored LUTs via --params + validate --from cube; never-read-.cube guardrail

- resolve -t lut / -t grade --params '<json>': build a parametric .cube from
  explicit params (bypassing the intent cascade), validate, and freeze in one
  step. --intent becomes the optional description. Lets an agent commit a look
  it computed itself.
- --from <file.cube> now validates the ingested LUT for lut/grade types and
  rejects an invalid/oversized cube (no partial write) — the escape hatch for a
  LUT the agent generated with its own code.
- SKILL.md: hard rule to never read a .cube body into context (~size^3 lines,
  zero legible signal) — inspect via grade-compare (see it) or cube-validate
  (ok/size), read the manifest description for meaning; plus both authoring
  paths and the parametric-vs-film-stock ceiling note.

Verified: media-use 116/116, lint + format clean; smokes — --params builds a
valid frozen cube, grade --params returns a lut block, bad JSON and an oversized
--from cube are both rejected with no stray file.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* fix(cli): grade-compare validates referenced LUTs, warns on no-op cells, caps candidates

Bug-bash follow-ups — grade-compare silently accepted bad input:

- Validate LUT *content*, not just existence: each referenced .cube is parsed
  with core's parseCubeLut (now exported from @hyperframes/core) and rejected
  with a per-cell error ("LUT for \"<label>\" is not a valid .cube: ..."). A
  file that exists but isn't a valid cube no longer renders a silent no-op cell.
- Warn on inactive cells: a grading that normalizes to inactive (e.g. a
  malformed {lut:12345}) emits a stderr warning naming the cell; the
  auto-prepended "original" baseline is intentionally inactive and stays silent.
  stdout remains valid JSON.
- Cap candidates at 16 (excluding baseline): over-cap input renders the first N
  and reports {truncated:true, total:M} on stdout + a stderr note — no silent
  drop, no unbounded giant sheet.

Verified: grade-compare 10/10; non-cube LUT → clear error; {lut:12345} → warning
+ ok; 20 cells → cells=17 truncated total=20; valid runs unchanged. Lint/format
clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* feat(cli): general `hyperframes compare` visual-variant primitive

Generalize grade-compare's "render N variants → one labeled sheet → the agent
looks and picks" loop into a standalone command that works on ANY variation
(font, layout, motion, grade, whole compositions) — the tool never needs to
know what differs.

- `hyperframes compare <path...> [--at <sec>] [--labels a,b,c] [--out] [--cols]
  [--json]`: renders each agent-authored composition variant through the real
  runtime (captureCompositionFrame) and stitches one labeled comparison sheet +
  JSON ({ok, sheet, rendered, variants, truncated?/total?}). 2+ paths required;
  caps at 16 with loud truncation. It presents, it does not judge — choosing is
  the caller's job.
- Factored the shared "render a labeled set → contact sheet" path so compare,
  grade-compare, and snapshot all sit on it (no duplication). grade-compare is
  now the first color-specific specialization of this primitive.
- New pathArgs util + contactSheet test; hyperframes-cli SKILL documents compare
  as the agent's "see your own renders and choose" primitive.

Verified: 26/26 across compare + grade-compare + snapshot + contactSheet (no
regressions); compare renders 3 variants into one visibly-distinct labeled
sheet; 2+-path error path clean; lint/format clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* fix(ci): green the skills CI — skip ffmpeg tests when absent, oxfmt markdown

The "Test: skills" CI job runs bare `node --test` with no ffmpeg on PATH (by
design — skills tests are meant to be node-builtin-only). The grade-analyzer +
smart-grade tests shell to ffmpeg and were failing there with ENOENT. Guard
them to skip when ffmpeg isn't on PATH; they still run locally / where it is.

Also oxfmt README.md + hyperframes/media-use SKILL.md (the whole-repo
`oxfmt --check .` Format job caught markdown left unformatted by the rebase
conflict resolution).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* fix(ci): skip core-conformance test when tsx is unavailable

The "Test: skills" CI job installs no deps, so the normalizeHfColorGrading
conformance test (which imports core's TS via `node --import tsx`) failed there.
Guard it to skip when tsx can't resolve; runs locally / in the deps-installed
Test job. Completes the skills-CI greening (the ffmpeg guards handled the rest).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* fix(cli): escape grade-compare src double-quotes (CodeQL XSS) + Windows-safe compare test

- grade-compare built `<img src="...">` (double-quoted) with the single-quote
  escaper, leaving `"` unescaped — a `"` in the frame path could break out
  (CodeQL: incomplete HTML attribute sanitization). Use escapeXml for src.
- compare label test hard-coded POSIX paths that can't match on Windows; assert
  the derived labels (the subject); path resolution is covered elsewhere.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* refactor(media-use): generate LUT library from params (drop committed .cube files)

The 3 bundled .cube files were 733 lines each (2,199 total) and were themselves
buildCube output — pure repo bloat. Replace with compact per-look params in
luts/index.json, generated on resolve; add an optional `url` for future scanned
LUTs to be CDN-hosted + downloaded on demand (freezeUrl) instead of committed.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* feat(media-use): serve library LUTs from CDN on-demand (static.heygen.ai/luts), params fallback

Looks now carry a CDN `url` (hosted at s3://heygen-public/luts → static.heygen.ai/luts/<id>.cube);
resolve downloads + validates + freezes on demand, like bgm/image. `params` stays
as the deterministic offline fallback (--local-only, or if the download fails), so
resolution is never blocked on the network. Provider prefers url, falls back to params.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

* fix(media-use): address #2041 review — atomic LUT writes, compare telemetry, follow-ups

- Atomic .cube writes: library provider (url + params) and the parametric
  generator now write to a .tmp path, validate, then rename, so a crash can
  never orphan an invalid .cube at the final path (was validate-after-write).
- track("media_use_resolve") now emits provenance.via (url/params-fallback/params).
- grade-compare + compare: --timeout flag (was hardcoded 5000) and a
  media_use_compare event (cells, truncated, total, render_ready_timed_out);
  openSettledCompositionPage now surfaces the render-ready timeout.
- compare staging skips node_modules/.git; --for gets an upfront existence check.
- Rec.709 luma comment; HYPERFRAMES_ANALYZE_TIMEOUT_MS override; measured note
  uses basename; LUT s3 hosting moved from index.json into luts/README.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H5k87mPZ4d6yiFwcWSb8Vv

---------

Co-authored-by: Claude Opus 4.8 (1M context) <[email protected]>

docs/guides/skills.mdx

@@ -98,7 +98,7 @@ Atomic capabilities the creation workflows compose against — pull one when you
 | `/hyperframes-animation` | All animation knowledge — atomic motion rules, scene blueprints, transitions, runtime adapters (GSAP / Lottie / Three.js / Anime.js / CSS / WAAPI / TypeGPU).         |
 | `/hyperframes-keyframes` | Seek-safe keyframe authoring across runtimes — GSAP timelines, CSS keyframes, Anime.js, WAAPI, FLIP, paths, masks, SVG morph/draw, 3D depth — plus `hyperframes keyframes` diagnostics for rendered motion. |
 | `/hyperframes-creative`  | Non-animation creative direction — `frame.md` / `design.md`, palettes, typography, narration, beat planning, audio-reactive visuals, composition patterns.            |
-| `/media-use`             | The media OS — resolve any media need (BGM, SFX, image, icon, logo, voice) into a frozen local file + ledger record, generate via TTS/music/image models when the catalog misses, transcribe, caption, remove backgrounds, and reuse assets across projects. One shared audio engine + manifest tracking.          |
+| `/media-use`             | The media OS — resolve any media need (BGM, SFX, image, icon, logo, voice, color grade, LUT) into a frozen local file or paste-ready block + ledger record, generate via TTS/music/image models when the catalog misses, transcribe, caption, remove backgrounds, and reuse assets across projects. One shared audio engine + manifest tracking.          |
 | `/hyperframes-cli`       | CLI dev loop — `init`, `lint`, `validate`, `inspect`, `preview`, `render`, `publish`, `doctor`, plus AWS Lambda cloud rendering (`lambda deploy / render / progress / destroy / policies`). |
 | `/hyperframes-registry`  | Install and wire registry blocks and components into compositions via `hyperframes add`. Authoring a new block or component to contribute upstream.                   |
 | `/figma`                 | Import Figma assets, tokens, components, and storyboard sections → reconstructed motion (frames read as states, not slides) (REST/CLI) plus Motion animations (MCP) and shaders (MCP source / native export) into a composition. |