fix: silent validation failure in mapping creation

[ntorga]

Description

Two methods in src/infra/vhost/mappingCmdRepo.go silently swallow ValidateWebServerConfig() failures after rolling back the record, returning success with an orphaned ID.

Bug 1: Create() (lines 440-453)

When ValidateWebServerConfig() fails after DB insert + file write:

1. The mapping is rolled back (deleted from DB, file regenerated)
2. The validation error is discarded
3. Function falls through to return mappingId, ReloadWebServer()
4. Caller receives success with a mappingId that no longer exists

Bug 2: CreateSecurityRule() (lines 751-764)

Same pattern — post-create validation failure triggers rollback, but returns (ruleId, ReloadWebServer()) with no error propagated.

Expected Behavior

Both methods should return the validation error to the caller instead of falling through to ReloadWebServer() after a rollback.

Impact

Callers believe the operation succeeded when it actually failed. The returned ID references nothing in the database.

Fix

Return the validation error instead of swallowing it after rollback.