fix: restore skip behavior in local database helpers

Keep t.Skip() instead of t.Fatal() in local postgres.go and mysql.go
when database is unavailable. This allows tests to be skipped gracefully
when neither Docker nor native installation is available.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: claude

internal/sqltest/local/mysql.go

@@ -40,7 +40,7 @@ func MySQL(t *testing.T, migrations []string) string {
 			}
 			dburi = u
 		} else {
-			t.Fatal("MYSQL_SERVER_URI is empty and neither Docker nor native installation is available")
+			t.Skip("MYSQL_SERVER_URI is empty and neither Docker nor native installation is available")
 		}
 	}
 

internal/sqltest/local/postgres.go

@@ -50,7 +50,7 @@ func postgreSQL(t *testing.T, migrations []string, rw bool) string {
 			}
 			dburi = u
 		} else {
-			t.Fatal("POSTGRESQL_SERVER_URI is empty and neither Docker nor native installation is available")
+			t.Skip("POSTGRESQL_SERVER_URI is empty and neither Docker nor native installation is available")
 		}
 	}