fix bugs, improve thread safety, add Javadoc across codebase

[g0ddest]

fix bugs, improve thread safety, add Javadoc across codebase

• fix delimiter regex treating literal strings as patterns (Pattern.quote)
• fix global mutable formatter registry by making it per-instance
• fix format() skipping null fields instead of padding them
• fix DefaultPredicate never filtering out in getPredicate()
• fix Scanner leak in parse() methods with try-with-resources
• fix getFieldValue catching Exception too broadly
• add formatter instance caching (ConcurrentHashMap)
• add DateFormatter thread-safe caching (ThreadLocal)
• add DateTimeFormatter caching for LocalDate/Time/DateTime formatters
• optimize Align.remove() from O(n²) to O(n)
• add failOnUnknownLines() and deprecate stopSkipUnknownLines()
• add field annotation validation (offset >= 1, length > 0)
• add records support via accessor method fallback in format()
• cache compiled Pattern for ignore regex
• add comprehensive Javadoc to all public classes and methods
• add tests for stream parsing, delimiters, validation, null formatting

[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
92.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud