Add ThreadLocal scoped values review

[JuanTorchia]

Summary

• Add THREAD_LOCAL source pattern detection to the textual scanner.
• Report direct ThreadLocal usage as a Java 21 -> 25 scoped-values review candidate.
• Keep the finding advisory: CONCURRENCY / INFO, no automatic rewrite recommendation.
• Add scanner and analyzer coverage for positive and negative transitions.
• Document the implementation in the engineering log.

Closes #10

Verification

• mvn -pl analyzer-core -Dtest=SourcePatternScannerTest test -> 4 tests passed
• mvn -pl analyzer-core test -> 20 tests passed
• mvn test -> 37 tests passed