Rename media-verify addon to Proofmode, remove CDR prefixes

Renames the addon from zammad-addon-media-verify to zammad-addon-proofmode
and removes all cdr_ prefixes from file names and class names per project
naming convention.

- Package: @link-stack/zammad-addon-proofmode (displayName: Proofmode)
- Classes: ProofmodeVerify, ProofmodeVerifyJob
- Files: proofmode_verify.rb, proofmode_verify_job.rb
- Settings: proofmode_verify_enabled
- Migration dir: db/addon/proofmode/

https://claude.ai/code/session_01GJYbRCFFJCJDAEcEVbD36N

packages/zammad-addon-proofmode/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "@link-stack/zammad-addon-proofmode",
+  "displayName": "Proofmode",
+  "version": "3.5.0-beta.1",
+  "description": "Zammad addon that verifies media attachments for C2PA and ProofMode data using the proofmode-rust library.",
+  "scripts": {
+    "build": "tsx scripts/build.ts",
+    "migrate": "tsx scripts/migrate.ts"
+  },
+  "dependencies": {
+    "@link-stack/zammad-addon-common": "workspace:*"
+  },
+  "devDependencies": {
+    "@types/node": "^24.7.0",
+    "tsx": "^4.20.6",
+    "typescript": "^5"
+  },
+  "author": "",
+  "license": "AGPL-3.0-or-later"
+}