feat(editing): shared resolveEditingAffordances (core) + studio re-point + SDK adapter (#1814)

* feat(core): add pure resolveEditingAffordances (edit capabilities + section applicability)

* fix(core): replace prohibited as-cast and !-assertions in isIdentityTransform

* refactor(studio): consume core resolveEditingAffordances; drop duplicated capability + section logic

- affordances.ts: add matrix3d identity-transform branch (was missing, caused test regression)
- domEditingLayers: add domEditSelectionToFacts mapper; resolveDomEditCapabilities is now a thin
  wrapper over core (kept for backward-compat — tests + barrel import it); isTextEditableSelection
  delegates to core sections.text; drop parsePx + isIdentityTransform imports (now in core)
- PropertyPanel: import resolveEditingAffordances + domEditSelectionToFacts; compute sections once;
  replace isMediaElement/isColorGradingCapableElement/timing inline check with sections.*
- propertyPanelMediaSection: delete isMediaElement (no remaining callers)
- propertyPanelColorGradingSection: delete isColorGradingCapableElement (no remaining callers)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat(sdk): add browser-only resolveElementAffordances adapter over core

* fix(sdk): add position to inlineStyles, replace ! assertion with guard in test

- Add missing 'position' key to inlineStyles in affordances.ts to match computedStyles
- Replace non-null assertion (doc.defaultView!) with proper null guard in test

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

* fix(editing): resolve code-review findings on affordances feature

Max-effort review (8 verified findings) fixes:

Correctness regressions (studio behavior):
- SVG selection crash: dropped `classNames` from EditableElementFacts
  entirely (it was never read by the resolver), which removes the
  `.className.split()` calls that throw on SVGElement (className is an
  SVGAnimatedString, not a string). Masked in tests by happy-dom.
- Timing panel hidden for GSAP-only layers: domEditSelectionToFacts now
  takes animationCount from the caller; PropertyPanel feeds the live
  gsapAnimations prop (selection.gsapAnimations is never populated).

Cleanups:
- Removed dead inline `position` key from SDK adapter (core reads position
  only from computedStyles).
- Added sections-only `resolveEditingSections` export; PropertyPanel uses it
  so panel re-renders no longer re-run the capability geometry parse.
- Declared happy-dom in packages/sdk devDependencies (was root-hoist only).
- Deduped the two capability fact-construction sites behind a shared
  capabilityFacts() helper.
- parsePx now has a single source of truth in core; studio domEditingDom
  re-exports it so the copies can't drift. isIdentityTransform is now
  core-internal (studio's only consumer moved to core in the prior task).

bun.lock also reconciles stale 0.7.17->0.7.21 package versions.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/studio/src/components/editor/domEditingDom.ts

@@ -19,39 +19,10 @@ export function isHtmlElement(value: unknown): value is HTMLElement {
 
 // ─── Style parsing ────────────────────────────────────────────────────────────
 
-export function parsePx(value: string | undefined): number | null {
-  if (!value) return null;
-  const trimmed = value.trim();
-  if (!trimmed.endsWith("px")) return null;
-  const parsed = parseFloat(trimmed);
-  return Number.isFinite(parsed) ? parsed : null;
-}
-
-export function isIdentityTransform(value: string | undefined): boolean {
-  const transform = (value ?? "none").trim();
-  if (!transform || transform === "none") return true;
-
-  const matrix = transform.match(/^matrix\(([^)]+)\)$/i);
-  if (matrix) {
-    const values = matrix[1].split(",").map((part) => Number.parseFloat(part.trim()));
-    if (values.length !== 6 || values.some((part) => !Number.isFinite(part))) return false;
-    return (
-      Math.abs(values[0] - 1) < 0.0001 &&
-      Math.abs(values[1]) < 0.0001 &&
-      Math.abs(values[2]) < 0.0001 &&
-      Math.abs(values[3] - 1) < 0.0001 &&
-      Math.abs(values[4]) < 0.0001 &&
-      Math.abs(values[5]) < 0.0001
-    );
-  }
-
-  const matrix3d = transform.match(/^matrix3d\(([^)]+)\)$/i);
-  if (!matrix3d) return false;
-  const values = matrix3d[1].split(",").map((part) => Number.parseFloat(part.trim()));
-  if (values.length !== 16 || values.some((part) => !Number.isFinite(part))) return false;
-  const identity = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1];
-  return values.every((part, index) => Math.abs(part - identity[index]) < 0.0001);
-}
+// Single source of truth lives in @hyperframes/core/editing so the studio
+// callers and the core resolver can't drift. Re-exported here to keep this
+// module's public surface (6 studio callers import parsePx from it).
+export { parsePx } from "@hyperframes/core/editing";
 
 export function isTextBearingTag(tagName: string): boolean {
   return ["div", "span", "p", "strong", "h1", "h2", "h3", "h4", "h5", "h6"].includes(tagName);