Revert guide: agent caret + reviewable agentInsertion highlights (#86 phase 6)

[hevayo]

Escape-hatch documentation for the agent-caret/highlight/review slice (grilled 2026-07-08), so it can be cleanly reverted if the character-exact application or the review gate causes trouble. Commits on feature-collab-with-agents will be listed here once shipped.

What the change does (and what a revert restores)

Area	With this change	After revert
Agent md edit application (@aep/collab-doc)	y-prosemirror updateYFragment minimal diff; inserted ranges formatted with the agentInsertion mark; caret relative-position returned	Whole-fragment reparse (delete-all + markdownToFragment), no marks, no caret — the #128 v1 behavior
Agent presence (services/agents room peer)	Publishes awareness cursor at its last insertion (CollaborationCaret renders it)	Avatar-only presence, no caret
Committer (services/collab)	Interim flushes SKIP md files with pending agentInsertion marks; forced flush on beforeUnloadDocument commits regardless (accept-by-default)	Every flush commits all changed files immediately (#133 behavior)
Console (SpecMdEditor)	Registers the shared mark + highlight styling; review bar (Accept all / Reject all) + per-range bubble menu	Plain editor; unknown-mark content in a live doc would ERROR in the editor schema — see revert order below
Schema (@aep/collab-doc markdown manager)	AgentInsertion mark in the shared schema; markdown serializer passes it through (committed md stays clean)	Mark absent from schema

Revert procedure

1. Revert the commits listed below (they will be scoped to this slice; git revert in reverse order).
2. Ordering caveat: live rooms may still hold docs containing agentInsertion attributes. Reverting the console/schema first would make the editor/serializer meet unknown marks. Safe sequence: restart collab-server AFTER the revert deploy (rooms die, docs reseed from clean git markdown — marks never persist to git by design, so a reseed is always clean).
3. Nothing to migrate in git history: committed markdown never contains marks; the review gate only delays flushes, so at most one pending session's edits flush late.

Why it might need reverting (watch for)

• updateYFragment diff pathologies (structure-heavy edits producing bad merges or duplicated nodes).
• The review hold-out starving commits (a file stuck unreviewed for a whole session while other edits pile up behind the gate).
• Markdown serializer mishandling the passthrough mark (marks leaking into committed markdown, or serialization errors in the committer).

Related: #86 (design comments: agent-edit application + reviewable additions), #133 (committer semantics this modifies), #130 (chat panel that triggers agent edits).

[hevayo]

Shipped on feature-collab-with-agents as cc91858 (cc9185892739172851ed488ddebf290eac08766c).

To revert this feature, revert that single commit:

git revert cc9185892739172851ed488ddebf290eac08766c

It contains the whole slice described above: @aep/collab-doc (AgentInsertion mark, markdownToNode, setDocFileAsAgent, hasPendingAgentMarks), the agents room-peer attribution + cursor awareness, the collab committer review gate (pendingChanges force/held + beforeUnloadDocument forced flush + lastToken), the console review UI (SpecMdEditor + agentReview.ts), the @aep/collab-doc dependency in apps/console/package.json, and the console Dockerfile's pnpm --filter @aep/collab-doc build step. Reverting it restores plain unattributed agent writes with debounce-only commits (#133 behavior).