fix(git-sync): unwedge per-page conflicts, preserve callout types, flush collab on disconnect

Addresses QA findings on PR #119 (issues #235/#236).

SYNC-WEDGE (HIGH): one same-line conflict on one page froze sync for the
WHOLE space in both directions forever. The pull's docmost->main merge left
the vault mid-merge, so every later cycle's isMergeInProgress() check returned
skipped:"merge-in-progress" and skipped the entire space with no recovery.
- pull.ts now COMMITS a conflicting merge with markers in place (commitMerge):
  cleanly-merged pages land, the conflicted page carries its markers on main and
  is isolated by the existing push-side conflict-marker skip (markers never reach
  Docmost), and the next cycle is no longer wedged. conflictedPaths is surfaced.
- cycle.ts now RECOVERS a vault left mid-merge by a prior/pre-fix cycle: it
  aborts the stale merge (merge --abort, hard-reset fallback) and continues,
  instead of skipping the space forever.
- git.ts: listUnmergedPaths / commitMerge / abortMerge / resetHardToHead.

CALLOUT TYPE FIDELITY: git-sync's CALLOUT_TYPES was missing "note" and "default"
(editor-canonical types), so [!note]/[!default] callouts flattened to [!info] on
every round-trip. Aligned the list with @docmost/editor-ext getValidCalloutType.

LOSS-ON-FAST-CLOSE: editing a page then closing the tab inside the collab
debounce window (~3-18s) lost the edit, because with unloadImmediately:false
Hocuspocus does not flush the debounced onStoreDocument on the last-client
disconnect. PersistenceExtension.onDisconnect now flushes the pending store
(debouncer.executeNow) on the last disconnect only, with no redundant write.

DUPLICATION re-verify (#1): the schema-default merge-key normalization is intact;
faithful toYdoc-based reproduction shows callout + rich content resync with 0 ops
and no growth/strip across cycles -> the re-report was leftover vault data, not a
live regression. Locked with a callout regression spec.

Tests: git-sync 688 pass (incl. real-VaultGit wedge-recovery integration); server
git-sync+collaboration 285 pass; new callout merge/fidelity + onDisconnect-flush
specs. tsc --noEmit clean.

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

packages/git-sync/src/lib/docmost-schema.ts

@@ -49,8 +49,18 @@ function getStyleProperty(element: HTMLElement, propertyName: string): string |
   return null;
 }
 
-/** Allowed Docmost callout types; anything else falls back to "info". */
-const CALLOUT_TYPES = ["info", "warning", "danger", "success"];
+/**
+ * Allowed Docmost callout types; anything else falls back to "info".
+ *
+ * This MUST stay in lockstep with the editor's canonical set
+ * (`getValidCalloutType` in `@docmost/editor-ext` callout/utils.ts:
+ * default | info | note | success | warning | danger). A type missing here is
+ * silently flattened to "info" on the markdown -> ProseMirror round-trip, so a
+ * `[!note]` / `[!default]` callout authored in the editor would come back as
+ * `[!info]` after a git sync (the QA "callout type -> [!info]" fidelity loss).
+ * `note` and `default` were previously absent and so were being flattened.
+ */
+const CALLOUT_TYPES = ["default", "info", "note", "success", "warning", "danger"];
 export const clampCalloutType = (value: string | null | undefined): string =>
   value && CALLOUT_TYPES.includes(value.toLowerCase())
     ? value.toLowerCase()