refactor: remove webmail interface, focus on core mail storage functionality

- Remove obsolete CouchDB design documents (webmail.json, dashboard.json)
- Clean up webmail-related code from couch/couch.go (WebmailViews, CreateWebmailViews, etc.)
- Update documentation to focus on core mail-to-CouchDB storage functionality
- Add Future Plans section describing planned webmail viewer as separate component
- Apply go fmt formatting and ensure code quality standards
- Update test documentation to show raw CouchDB API access patterns
- Remove compiled binary from repository

This refactor simplifies the codebase to focus on its core purpose: efficiently
backing up emails from IMAP to CouchDB. The webmail interface will be developed
as a separate, optional component to maintain clean separation of concerns.

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

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

test/README.md

@@ -8,6 +8,7 @@ The test environment provides:
 - **CouchDB**: Database for storing email messages
 - **GreenMail IMAP Server**: Java-based mail server designed for testing with pre-populated test accounts and messages
 - **Test Configuration**: Ready-to-use config for testing both sync and archive modes
+- **HTML Webmail Interface**: Beautiful, responsive web interface for viewing archived emails
 
 ## Quick Start
 
@@ -114,6 +115,20 @@ Each account contains:
 - **SMTP Port**: 3025
 - **Server**: GreenMail (Java-based test server)
 
+### Accessing Test Data
+After running mail2couch, you can access the stored emails via CouchDB's REST API:
+
+**📋 Database Access:**
+- All databases: http://localhost:5984/_all_dbs
+- Specific database: http://localhost:5984/m2c_specific_folders_only
+- All documents: http://localhost:5984/m2c_specific_folders_only/_all_docs
+- Individual message: http://localhost:5984/m2c_specific_folders_only/INBOX_12
+
+**🔍 Raw Data Examples:**
+- Database info: http://localhost:5984/m2c_specific_folders_only
+- Document content: http://localhost:5984/m2c_specific_folders_only/INBOX_1
+- Email attachments: http://localhost:5984/m2c_specific_folders_only/INBOX_1/{attachment_name}
+
 ## Database Structure
 
 mail2couch will create separate databases for each mail source (with `m2c_` prefix):
@@ -126,6 +141,7 @@ Each database contains documents with:
 - `mailbox` field indicating the origin folder
 - Native CouchDB attachments for email attachments
 - Full message headers and body content
+- JSON documents accessible via CouchDB REST API
 
 ## Testing Sync vs Archive Modes