The PROPFIND handlers (added in #153) handle the /caldav/{username}/ and
/carddav/{username}/ prefixes returned by discovery, but do so via an
expensive database call to distinguish usernames from UUIDs. The remaining
handlers (PUT, GET, DELETE, REPORT, PROPPATCH) don't handle the prefix
at all, causing 500 errors when standard clients (DAVx5, Apple Calendar,
Thunderbird) follow the discovery URLs.
This commit:
1. Adds a strip_username_prefix() helper that uses a UUID parse check
to distinguish collection IDs from usernames (no DB call needed).
2. Applies it to PUT, GET, DELETE, REPORT, and PROPPATCH handlers in
both caldav_handler.rs and carddav_handler.rs.
3. Refactors PROPFIND in both files to use the same UUID heuristic for
consistency, avoiding unnecessary database queries.
Includes 7 unit tests for the helper function.
Timm
d0086bb433