nisse-review: match repository patterns against Gitea's search

At bring-up, `dev/*` failed: listing an organization's repositories
(/orgs/dev/repos) needs the read:organization token scope, which the
reviewer's token doesn't have and shouldn't need. Patterns are now matched
against /repos/search, which needs only the repository scope and already
lists every repository the account can read. A pattern that matches
nothing is logged (access.no_match). owner_repositories goes.

A Gitea error at startup is now reported like a config error, not a
traceback.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-review/src/nisse_review/main.py

@@ -9,6 +9,7 @@ from types import FrameType
 
 from nisse_core.config import ConfigError
 from nisse_core.envfile import load_env_file
+from nisse_core.gitea import GiteaError
 from nisse_review.access import AccessRefused
 from nisse_review.build import StartupError, build
 from nisse_review.config import ReviewConfig
@@ -19,7 +20,7 @@ def main() -> int:
     try:
         config = ReviewConfig.load()
         built = build(config)
-    except (ConfigError, StartupError) as exc:
+    except (ConfigError, StartupError, GiteaError) as exc:
         print(f"nisse-review: {exc}", file=sys.stderr)
         return 2