fix: reject host-less catalog URLs in base and preset validators (#3209) (#3227)

`CatalogStackBase._validate_catalog_url` (inherited by `IntegrationCatalog`)
and `PresetCatalog._validate_catalog_url` checked `parsed.netloc`, which is
truthy for host-less URLs like `https://:8080` (port only) or `https://user@`
(userinfo only). Such URLs slipped past validation despite the error message
promising "a valid URL with a host", then failed later with a confusing fetch
error.

Switch both validators to `parsed.hostname` (None for those inputs), matching
the workflow, step, and bundler catalog validators that already do this.

Add regression tests covering port-only and userinfo-only URLs for both
validators.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/specify_cli/catalogs.py

@@ -80,7 +80,7 @@ class CatalogStackBase:
             )
         # Check hostname, not netloc: netloc is truthy for host-less URLs like
         # "https://:8080" or "https://user@", so the host guarantee this error
-        # promises would not actually hold. hostname is None in those cases.
+        # promises would not actually hold. hostname is None in those cases (#3209).
         if not parsed.hostname:
             raise cls._error("Catalog URL must be a valid URL with a host.")
 

src/specify_cli/presets/__init__.py

@@ -1863,7 +1863,7 @@ class PresetCatalog:
             )
         # Check hostname, not netloc: netloc is truthy for host-less URLs like
         # "https://:8080" or "https://user@", so the host guarantee this error
-        # promises would not actually hold. hostname is None in those cases.
+        # promises would not actually hold. hostname is None in those cases (#3209).
         if not parsed.hostname:
             raise PresetValidationError(
                 "Catalog URL must be a valid URL with a host."