Treat libinjection parser errors as matches in DetectSQLi/DetectXSS and add benign regression tests

[Easton97-Jens]

Motivation

• Update the SQLi and XSS detection operators to handle the newer libinjection return codes and ensure parser errors are handled as fail-safe matches.
• Capture input when libinjection reports an error so rules with capture still receive context for diagnostics.
• Add regression tests for benign inputs to verify no false positives for both operators.

Description

• Include libinjection_error.h and switch to injection_result_t return values from libinjection_sqli and libinjection_xss for explicit handling of TRUE, FALSE, and ERROR outcomes.
• Treat LIBINJECTION_RESULT_ERROR as a match (fail-safe) and log a parser error message while storing the raw input into TX.0 when capture is enabled.
• Preserve previous behavior for positive detections by pushing fingerprints (SQLi) or storing the input (XSS) on matches and keep logging for non-matches.
• Add benign regression cases in test/test-cases/regression/operator-detectsqli.json and test/test-cases/regression/operator-detectxss.json to assert no matches for safe inputs.

Testing

• Ran the regression test cases including the updated operator-detectsqli.json and operator-detectxss.json files; all tests completed successfully.
• Verified existing malicious test cases still produce matches and capture behavior succeeded for @detectSQLi and @detectXSS.
• No automated test failures were observed after the changes.

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Codex Task

[chatgpt-codex-connector]

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