ProdCom 1.3.0: one connection to ProdCom, shared by every dashboard

The module used to proxy each browser's transcript stream to ProdCom one
to one, so N screens meant N upstream connections and N history reads.
It now follows ProdCom once: it keeps the channel list, the groups and
the last 300 entries, and gives every browser a snapshot on connect
(`state`) plus each changed entry as it happens (`entry`), with `clear`
and `status` frames as the link changes. Reconnects back off from 2 s to
15 s, re-read the lists and history, and re-send the snapshot. The tile
no longer loads anything itself; the admin readout says how many channels
and entries the server holds. The /prodcom/* proxy is gone.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

modules/prodcom-transcript/module.json

@@ -1,9 +1,9 @@
 {
   "id": "prodcom-transcript",
   "name": "ProdCom",
-  "version": "1.2.2",
+  "version": "1.3.0",
   "proddash": ">=1.1.0",
-  "description": "Live ProdCom transcript stream",
+  "description": "Live ProdCom transcript",
   "permissions": [
     {
       "kind": "local-network",