test(core,studio): add T3+T7 hfId targeting stubs (spec for R1) (#1267)

* test(studio): add T5b rotation+motion build-patches characterization

Extends manualEditsDomPatches.test.ts with rotation and motion pairs.
Same 4-pattern structure: populated, empty, clear restores originals,
build/clear symmetry. Merges duplicate manualEditsTypes import block.

* test(studio): add T5c review-fix gaps in manualEditsDomPatches characterization

Fixes four gaps identified in max-setting code review:
- Box-size clear: replace arrayContaining with full ordered toEqual (30 ops)
- Box-size / pathOffset / rotation clear: add empty-string coercion tests
  (origVal||null must produce null, not set property to "")
- Rotation clear: add test for absent STUDIO_ORIGINAL_ROTATION_TRANSFORM_ORIGIN_ATTR
- Motion clear: prove input-independence by calling with both empty and populated
  element and asserting identical output

* refactor(core): extract maxEndTime+serialize to parsers/test-utils.ts (TU)

Deduplicate helpers shared by T1 (htmlParser.roundtrip.test.ts) and T2
(stableIds.test.ts). Both files inline identical implementations; extract
to test-utils.ts so future parser tests (T6a…) import one copy.

Also fix lefthook fallow command to unset GIT_DIR+GIT_INDEX_FILE before
running — those vars are set by git in worktree hook context and block
fallow’s internal temp-worktree creation.

* test(core): add T10 PreviewAdapter contract stubs (spec for R7)

All 14 tests are it.todo, following the T4 pattern. The stubs define the
full createPreviewAdapter interface — elementAtPoint (root exclusion,
hf-id ancestor walk, opacity filter), applyDraft/revertDraft (draft
marker lifecycle), commitPreview (patch derivation), and getElementTimings
(data-start/data-end reader).

createPreviewAdapter does not exist yet; R7 implements it and converts
these stubs to real assertions.

* test(core): add T6a GSAP parser golden baselines (Recast/Babel snapshot)

6 toMatchFileSnapshot tests across 3 representative scripts (minimal,
moderate, complex). Captures parseGsapScript + serializeGsapAnimations
output before the Recast → Meriyah swap so any parser change is detected
as a golden diff rather than a silent behavioral regression.

Goldens live in src/parsers/__goldens__/ and are checked in. Add
__goldens__/** to fallow ignorePatterns (data files, not modules) and to
.prettierignore so oxfmt does not reformat vitest-written snapshot files.

* test(core,studio): add T3+T7 hfId targeting stubs (spec for R1)

T3 (sourcePatcher.test.ts): 5 it.todo stubs for PatchTarget.hfId targeting
— style, text, attribute patches plus preservation and fallthrough cases.

T7 (sourceMutation.test.ts): 2 it.todo stubs for SourceMutationTarget.hfId
— basic patch and data-hf-id survival after patch.

Neither interface has hfId yet. R1 adds the field + [data-hf-id="…"] branch
in findTagByTarget / findTargetElement, then converts these to real assertions.

packages/core/src/studio-api/helpers/sourceMutation.test.ts

@@ -361,3 +361,12 @@ describe("probeElementInSource", () => {
     expect(probeElementInSource(sourceHtml, { id: "canvas" })).toBe(true);
   });
 });
+
+// T7 — data-hf-id targeting (spec for R1).
+// R1 adds `hfId?: string` to SourceMutationTarget and a `[data-hf-id="…"]` branch
+// in findTargetElement (sourceMutation.ts:34). Convert from it.todo in the R1 PR.
+describe("T7 — data-hf-id targeting (spec for R1)", () => {
+  it.todo("patches element by data-hf-id when no HTML id attribute is present");
+
+  it.todo("data-hf-id attribute survives the patch (can be targeted again)");
+});