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>

CLAUDE.md

@@ -57,7 +57,7 @@ cd go && go mod tidy
 2. **Mail Handling (`mail/`)**: IMAP client implementation
    - Uses `github.com/emersion/go-imap/v2` for IMAP operations
    - Supports TLS connections
-   - Currently only lists mailboxes (backup functionality not yet implemented)
+   - Fetches and processes email messages from IMAP mailboxes
 
 3. **CouchDB Integration (`couch/`)**: Database operations
    - Uses `github.com/go-kivik/kivik/v4` as CouchDB driver
@@ -95,7 +95,7 @@ This design ensures the same `config.json` format will work for both Go and Rust
 - ✅ Per-account CouchDB database creation and management
 - ✅ IMAP connection and mailbox listing
 - ✅ Build error fixes
-- ✅ Email message retrieval framework (with placeholder data)
+- ✅ Real IMAP message retrieval and parsing
 - ✅ Email storage to CouchDB framework with native attachments
 - ✅ Folder filtering logic with wildcard support (`*`, `?`, `[abc]` patterns)
 - ✅ Date filtering support
@@ -103,7 +103,6 @@ This design ensures the same `config.json` format will work for both Go and Rust
 - ✅ Duplicate detection and prevention
 - ✅ Sync vs Archive mode implementation
 - ✅ CouchDB attachment storage for email attachments
-- ✅ Real IMAP message parsing with go-message library
 - ✅ Full message body and attachment handling with MIME multipart support
 - ✅ Command line argument support (--max-messages flag)
 - ✅ Per-account CouchDB databases for better organization
@@ -143,6 +142,7 @@ Sync metadata documents are stored in CouchDB with ID format: `sync_metadata_{ma
 - Comprehensive test environment with Podman containers and automated test scripts
 - The application uses automatic config file discovery as documented above
 
+
 ### Next Steps
 
 The following enhancements could further improve the implementation:
@@ -158,4 +158,5 @@ The following enhancements could further improve the implementation:
 ## Development Guidelines
 
 ### Code Quality and Standards
-- All code requires perfect linting and tool-formatting, exceptions are allowed only if documented properly
+- All code requires perfect linting and tool-formatting, exceptions are allowed only if documented properly
+- We always want linting and formatting of our code to be perfect