fix(platform): Phase 729 dual-heal gossip keys and HyperDB extract

Repair corrupted voice/stage/screen dual-heal mixins (wrong thread gossip
keys and heal contexts). Regenerate 14 dual-heal legacy json mixins with
per-entry keysField/initMethod; add json-export-gossip-registry alignment
tables and platform-hyperdb-sync.js from index.js. Behavior unchanged;
mesh dedupe now matches dedicated export mixins where aligned.

Co-authored-by: Cursor <[email protected]>

platform-hyperdb-sync.js

@@ -0,0 +1,36 @@
+'use strict'
+
+/** HyperDB uint fields must be positive integers. */
+function coerceSyncUint (v, fallback = 0) {
+  const n = Number(v)
+  const fb = Math.max(1, Math.floor(Number(fallback) || 1))
+  if (!Number.isFinite(n) || n <= 0) return fb
+  return Math.floor(n)
+}
+
+function sanitizeMessageForHyperDb (msg) {
+  if (!msg || typeof msg !== 'object') return msg
+  const row = { ...msg }
+  row.createdAt = coerceSyncUint(row.createdAt, Date.now())
+  if (row.editedAt != null && row.editedAt !== '') {
+    const ed = Number(row.editedAt)
+    row.editedAt =
+      Number.isFinite(ed) && ed > 0 ? Math.floor(ed) : null
+  }
+  return row
+}
+
+function sanitizeMemberForHyperDb (mem) {
+  if (!mem || typeof mem !== 'object') return mem
+  const row = { ...mem }
+  row.joinedAt = coerceSyncUint(row.joinedAt, Date.now())
+  if (row.updatedAt != null) row.updatedAt = coerceSyncUint(row.updatedAt, row.joinedAt)
+  if (row.createdAt != null) row.createdAt = coerceSyncUint(row.createdAt, row.joinedAt)
+  return row
+}
+
+module.exports = {
+  coerceSyncUint,
+  sanitizeMessageForHyperDb,
+  sanitizeMemberForHyperDb
+}