feat: track element deletions in the agent context

[rezailmi]

Summary

Deleting an element in the overlay was invisible to coding agents. deleteSelection removed the element's session edit entirely and recorded the removal only in the local undo stack, so nothing in the exported/sent context told the agent to remove the element from source. If you styled an element and then deleted it, even the styling edit was wiped.

This PR makes deletions first-class session edits that flow to agents through every send/copy surface.

What changed (feature — 80fe237)

• types.ts — optional deleted?: boolean on SessionEdit.
• use-session-manager.ts — deleteSelection marks the edit deleted: true (capturing the locator before DOM removal) instead of dropping it; undo restores the prior state. getSessionEdits keeps deleted edits and only prunes genuinely-stale disconnected ones (!isConnected && !deleted).
• utils.ts — hasSessionEditChanges counts deletions; buildSessionExport emits an action: delete this element block; getExportContentProfile/buildExportInstruction gain a delete directive.
• use-agent-comms.ts — the per-item send adds deleted: true to the agent payload; apply-all/copy-all pick it up via getSessionItems.
• edits-popover.tsx — deleted items render as deleted: <element>.

Code review fixes (7559cc6)

Ran a structured multi-agent review (8 reviewers). One real defect surfaced and is fixed here:

• P1 — move + delete contradiction: a deleted element that also had a pending move emitted a "move this element" plan alongside "delete this element". Fixed at the root in buildMoveEntries (a deleted edit produces no move intent/plan/profile-flag). Kept deleted-and-moved edits visible in the popover.
• Documented the new deleted field in the mcp-server, runner-workflow, and mac-app-integration contracts.
• Added tests: delete+move suppression, the deleted:true payload reaching the agent, and multi-element deletion tracking.

Also included (docs — a8e1aaf)

Backlog implementation plans 010–017 under plans/ (utils god-module slice, overlay/canvas tests, color-scan perf, eslint+prettier, test:fast, preload version field, rotated-drag scale, provider footer wiring). Pure planning docs — no code impact. Split into its own commit if you'd prefer a separate PR.

Verification

• bunx tsc --noEmit clean; bun run test green (515 tests, +7 from baseline).
• Live: deleted an element in the dev app and confirmed it appears in the "Copy to AI agents" popover as deleted: ….

Notes / follow-ups

• The deleted field rides to the out-of-repo Mac app broker; even if stripped, exportMarkdown carries the delete instruction. Confirm passthrough (same open question as moveIntent/movePlan).
• When the session-edit stale lifecycle (plan 006) lands, its reconciler must skip deleted edits and extend the getSessionEdits guard.