# Mail Processing Stabilization Phase – NEW Camel mail route

This patch adds a NEW-runtime Camel route for mail ingestion that is similar in purpose to the legacy `MailRoute`, but implemented only in the NEW code path (`at.procon.dip.*`).

## Scope

- runtime mode: `NEW` only
- entrypoint: Camel mail consumer route
- downstream handling: `DocumentIngestionGateway` with `SourceType.MAIL`
- no legacy profile/config/code changes

## Main classes

- `at.procon.dip.ingestion.camel.GenericMailIngestionRoute`
- `at.procon.dip.ingestion.mail.MailServerEndpointUriFactory`
- `at.procon.dip.ingestion.mail.CamelMailServerEndpointUriFactory`
- `at.procon.dip.ingestion.mail.MailServerProtocol`

## Configuration

Configured under `dip.ingestion.mail-route` in `application-new.yml`.

Supported protocols currently exposed through the generic endpoint factory:
- `IMAP`
- `IMAPS`
- `POP3`
- `POP3S`

This keeps the route provider/protocol-agnostic at the configuration level while still using Apache Camel mail endpoints underneath.

## Behavior

When enabled, the route:
1. consumes messages from the configured mail endpoint
2. serializes each provider message to raw MIME bytes
3. extracts basic provider/provenance attributes
4. builds a `SourceDescriptor` with `SourceType.MAIL`
5. delegates the actual parsing/import/attachment handling to the existing NEW `MailDocumentIngestionAdapter`

## Provenance attributes added by the route

The route enriches the `SourceDescriptor.attributes` map with:
- `providerType`
- `providerProtocol`
- `providerAccountKey`
- `providerFolderKey`
- `providerMessageKey` (when available from Camel headers)
- `providerThreadKey` (when available)
- `messageId`
- `subject`
- `from`

## Notes

- The route intentionally does **not** depend on `TedProcessorProperties`.
- The route is designed for the NEW runtime only.
- The mail import behavior still relies on the NEW `MailDocumentIngestionAdapter` for MIME parsing and attachment import.
- This step does not add replay/reprocessing yet.
