feat(studio): route element delete through SDK removeElement (§3.1)

[vanceingalls]

Summary

Routes handleDomEditElementDelete through the SDK (sdkSession.removeElement) when an active session resolves the element's hf-id, falling back to the existing server-side /api/projects/{pid}/file-mutations/remove-element/ path otherwise. Also documents (via // ponytail: comment) that z-index reorder (§3.4) is already SDK-cut-over because it writes inline-style patches through commitPositionPatchToHtml → persistDomEditOperations → onTrySdkPersist.

Stage 7 §3.1 — Delete → removeElement

Changes

• sdkCutover.ts: Extract internal persistSdkSerialize helper (serialize → write → recordEdit → reload tail shared across ops); add exported sdkDeletePersist(hfId, originalContent, targetPath, session, deps). sdkCutoverPersist refactored to use persistSdkSerialize.
• useElementLifecycleOps.ts: Add optional onTrySdkDelete? callback to params; handler tries it after reading originalContent and before the server API call. On success: clear selection, show toast, return. Z-index reorder // ponytail: note added (§3.4 verified cut-over).
• useDomEditCommits.ts: Thread onTrySdkDelete? through UseDomEditCommitsParams → useElementLifecycleOps.
• useDomEditSession.ts: Wire onTrySdkDelete from sdkSession (same pattern as onTrySdkPersist).
• sdkCutover.test.ts: 6 new tests for sdkDeletePersist (null session, element not found, removeElement called, history recorded, reload called, error fallback).

Open decisions (§7)

• Undo ownership (D): sdkDeletePersist records into Studio editHistory (persistent), consistent with sdkCutoverPersist. SDK session also has in-memory history. Two stacks coexist — same as style/text edits today. s7.4 force-reload after undo/redo keeps Studio history authoritative; no regression introduced.
• §3.4 z-index reorder: Writes inline-style patches → already SDK-cut-over as setStyle. No DOM-node reordering; no SDK reorder op exists or is needed. Documented with // ponytail: comment.

Verification

• bun run build ✅
• bun run test ✅ (26 sdkCutover tests pass, full suite green)
• bunx oxlint / bunx oxfmt --check ✅
• 600-line file gate ✅
• Lefthook pre-commit hooks ✅

🤖 Generated with Claude Code

[vanceingalls]

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

• feat(studio): route GSAP keyframe add through SDK (§3.5 PR2) #1470
• feat(studio): route GSAP tween add/update/delete through SDK (§3.5 PR1) #1469
• chore(studio): document CSS-path position cut-over; GSAP-path deferred (§3.3) #1467
• feat(studio): route timeline trim/move through SDK setTiming (§3.2) #1466
• feat(studio): route element delete through SDK removeElement (§3.1) #1465 👈 (View in Graphite)
• fix(studio): wire onTrySdkPersist to sdkCutoverPersist (cutover was unwired) #1463
• feat(studio): s7.5 — make sdk cutover always-on, delete shadow scaffolding #1462
• fix(studio): force-reload sdk session after undo/redo bypasses suppress window #1460
• main

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