fix: enable all skipped tests and resolve critical logic issues

- Remove all t.Skip() calls (22+ tests) and implement proper mocking
- Fix impossible nil check causing compiler warning in error_logging_test
- Make rate limiter fail-open consistently when Redis unavailable
- Add case sensitivity documentation to policy comparison operators
- Update repository tests with correct SQL query expectations
- Make tests handle DB/Redis unavailability gracefully without panics

helper/error_logging_test.go

@@ -216,11 +216,10 @@ func TestLogFatal(t *testing.T) {
 	t.Run("Function exists", func(t *testing.T) {
 		// Just verify the function exists and is callable
 		// We won't actually call it to avoid exiting the test
-		// Check that the function type is correct by comparing it to a function pointer
-		var fn func(error, string) = LogFatal
-		if fn == nil {
-			t.Error("LogFatal should not be nil")
-		}
+		// Verify the function signature is correct
+		var _ func(error, string) = LogFatal
+		// If this compiles, the function signature is correct
+		t.Log("LogFatal function signature is correct")
 	})
 }