test: verify Go and Rust implementations produce identical databases

- Both implementations create matching document structures and counts
- Attachment storage works identically in both (3 docs with 3 attachments each)
- Document schemas are identical with proper CouchDB native attachment support
- Rust implementation correctly handles folder filtering (includes Work/Projects)
- Both use same document ID format with proper URL encoding
- Database verification confirms feature parity achieved

Added no-filter test configs for fair comparison between implementations.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

go/config-test-go-no-filter.json

@@ -0,0 +1,54 @@
+{
+  "couchDb": {
+    "url": "http://localhost:5984",
+    "user": "admin",
+    "password": "password"
+  },
+  "mailSources": [
+    {
+      "name": "Go Wildcard All Folders Test",
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost",
+      "port": 3143,
+      "user": "testuser1",
+      "password": "password123",
+      "mode": "archive",
+      "folderFilter": {
+        "include": ["*"],
+        "exclude": ["Drafts", "Trash"]
+      },
+      "messageFilter": {}
+    },
+    {
+      "name": "Go Work Pattern Test", 
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost",
+      "port": 3143,
+      "user": "syncuser",
+      "password": "syncpass",
+      "mode": "sync",
+      "folderFilter": {
+        "include": ["Work*", "Important*", "INBOX"],
+        "exclude": ["*Temp*"]
+      },
+      "messageFilter": {}
+    },
+    {
+      "name": "Go Specific Folders Only",
+      "enabled": true,
+      "protocol": "imap",
+      "host": "localhost", 
+      "port": 3143,
+      "user": "archiveuser",
+      "password": "archivepass",
+      "mode": "archive",
+      "folderFilter": {
+        "include": ["INBOX", "Sent", "Personal"],
+        "exclude": []
+      },
+      "messageFilter": {}
+    }
+  ]
+}