fix(web): fully remove payload runtime from production build

Remove ALL Payload imports, withPayload wrapper, and (payload)
routes. Blog index + changelog are now static data arrays.
Blog post at /blog/peer-messaging-claude-code is static TSX.

Payload CMS stays as a dev dependency for future local admin
but has zero presence in the production build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/db/migrations/meta/_journal.json

@@ -22,6 +22,13 @@
       "when": 1775340519054,
       "tag": "0002_vengeful_enchantress",
       "breakpoints": true
+    },
+    {
+      "idx": 3,
+      "version": "7",
+      "when": 1775463897329,
+      "tag": "0003_add-presence-summary",
+      "breakpoints": true
     }
   ]
 }