feat(studio): add keyframe ease editor

[miguel-heygen]

What

Add the complete Studio keyframe ease editor: preset selection, Curve/Spring/Wiggle modes, parameter fields, editable curve visualization, and telemetry.

This is Family A, PR 3 of 4. Prerequisite: codex/studio-timeline-a-parser-intent-v2. Next: codex/studio-timeline-a-array-timing-v2.

Replacement review history: #2572 and #2562. Golden reference: #2387.

Why

Users need one coherent editor for every easing mode. The controls and inspector consume the same preset and curve contracts, so publishing only one half creates an invalid intermediate UI and a non-typechecking branch.

How

The editor centralizes preset metadata, curve SVG rendering, parameter controls, inspector composition, and analytics events. This PR is the recorded Family A size exception: 1,589 changed lines. Splitting it further would introduce temporary plumbing, duplicate APIs, and an independently broken intermediate branch.

Test plan

• Unit tests added/updated — 51 focused Studio editor and telemetry tests passed at this PR boundary
• Manual testing performed — Curve, Spring, Wiggle, presets, and inspector interactions passed the certified Studio browser matrix
• Documentation updated (not applicable; Studio UI)

[miguel-heygen]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• fix(parsers): preserve duration-authored keyframe timing #2675
• feat(studio): add keyframe ease editor #2674 👈 (View in Graphite)
• fix(parsers): preserve authored keyframe intent #2673
• feat(core): add deterministic keyframe ease runtime #2672
• main

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