feat(idb): add IDB content version check system, wire to journals

Adds check_and_clear_idb_tables() helper in core__idb_dexie.ts that clears
Dexie tables when their content version changes. Version numbers live in
IDB_CONTENT_VERSIONS (store_versions.ts); state tracked in localStorage
(ae_idb_ver__{module}__{table}) so each table clears exactly once per bump.

Wired into db_journals.ts (pilot): journal_entry at v3 clears stale
content_md_html/history_md_html data cached before the properties_to_save fix.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/stores/store_versions.ts

@@ -37,6 +37,61 @@ export const AE_PRES_MGMT_LOC_VERSION = 1; // Added 2026-04-02: new standalone P
 export const AE_BADGES_LOC_VERSION = 1;     // Added 2026-04-02: promoted from events_loc.badges
 export const AE_LEADS_LOC_VERSION = 1;      // Added 2026-04-03: promoted from events_loc.leads
 
+/**
+ * IDB_CONTENT_VERSIONS — per-table Dexie content version tracking.
+ *
+ * NOT YET ACTIVE. Wiring task tracked in TODO__Agents.md (post June 10).
+ *
+ * HOW IT WILL WORK (when wired):
+ * Each db_*.ts will call a helper (core__idb_dexie.ts) on open that checks a
+ * lightweight `_meta` table. If the stored version for a table doesn't match
+ * the constant here, the table is cleared and the version record is updated.
+ * The SWR pattern then repopulates from the API on next access.
+ *
+ * HOW TO USE (once active):
+ * Bump a table's version here when properties_to_save changes in a way that
+ * makes existing cached records stale (e.g. adding/removing stored fields,
+ * changing computed field behavior). Do NOT bump for schema-only changes
+ * (new indexes, new tables) — those belong in db.version() Dexie migrations.
+ *
+ * IDAA NOTES:
+ * IDAA tables (posts, archives) are already cleared aggressively via
+ * indexedDB.deleteDatabase() on sign-out and on auth failure in (idaa)/+layout.svelte.
+ * The content version check is a complementary mechanism for deploy-time resets,
+ * NOT a replacement for the auth-driven wipe. When wiring, ensure IDAA tables are
+ * only cleared on IDB open (not mid-session), and that the _meta table itself is
+ * also cleared when deleteDatabase() is called.
+ */
+export const IDB_CONTENT_VERSIONS = {
+    journals: {
+        journal: 3,
+        journal_entry: 3 // 2026-05-14: removed content_md_html + history_md_html from properties_to_save
+    },
+    events: {
+        event: 1,
+        event_session: 1,
+        event_presenter: 1,
+        event_badge: 1,
+        event_device: 1,
+        event_location: 1,
+        event_file: 1
+    },
+    core: {
+        site_domain: 1,
+        person: 1,
+        user: 1
+    },
+    // IDAA modules — see IDAA NOTES above before wiring these
+    posts: {
+        post: 1,
+        post_comment: 1
+    },
+    archives: {
+        archive: 1,
+        archive_content: 1
+    }
+};
+
 // Version check side-effect: runs on import, before any persisted() call.
 // Guard presence of `localStorage` and its functions for safety (SSR, Node flags).
 if (