[littlegrasscao]

Summary

• add RecipientEntity and RecipientTokenEntity persistence and the provider recipient API, served by RecipientAdminService:
  • POST /recipients, GET /recipients, GET /recipients/{recipient}, PATCH /recipients/{recipient}, DELETE /recipients/{recipient}
• RecipientService.create calls catalog.authorize(CREATE_RECIPIENT); the catalog's userId becomes the owner, and only the owner may update or delete the recipient
• names are stored lowercase and looked up in any case; deleting a recipient deletes its tokens
• owner changes to a recipient load it with SELECT ... FOR UPDATE, so concurrent changes to one recipient run one at a time; an update that waits on a delete gets 404
• creating a recipient issues a one-time activation code, and responses carry its activationUrl
• activation links are built on a new required server.public-url setting, the address recipients reach the server at, rather than the address the provider's request arrived on, which can be internal to a proxy. The server fails to start without it, and it must be an http or https URL
• reading recipients is not limited yet; TODOs mark where USE_RECIPIENT will apply

Testing

• mvn clean install: 100 tests passed
• RecipientServiceTest: creating a recipient requires CREATE_RECIPIENT from the catalog
• RecipientAdminServiceTest: recipient CRUD over HTTP as the owner, case-insensitive gets, owner-only updates and deletes, and 401 without a token the catalog accepts
• PublicUrlTest: startup fails without server.public-url, invalid values are rejected, and activation links use the public URL rather than the request address
• TestServer sets server.public-url to its own address; OpenSharingServerTest and UnknownRouteTest set one so the server starts