Add ignore-case overloads for startWith, replace, and replaceAll

[mrMigles]

Motivation

• Enable case-insensitive text searching and replacements from scripting by adding boolean ignoreCase overloads for startWith, replace and replaceAll so scripts can match or replace without regard to case.
• Consolidate case-insensitive logic in helpers to avoid duplicated code for literal and regex replacements.
• Cover the new behavior with unit tests to prevent regressions.

Description

• Added startWith(String text, boolean ignoreCase) which uses StringUtils.startsWithIgnoreCase when ignoreCase is true and falls back to String.startsWith otherwise.
• Added replace(..., boolean ignoreCase) and replaceAll(..., boolean ignoreCase) overloads for the existing variants (literal and Function<ScriptContext,String> parameters) and centralized helpers replaceLiteral and replaceAllRegex to implement case-insensitive behavior using StringUtils.replaceIgnoreCase and Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE respectively.
• Updated AbstractTextAndNumberOperationsTest to assert the new startWith(..., true/false), replace(..., true/false) and replaceAll(..., true) behaviors.

Testing

• Ran the unit test command ./mvnw -q -Dtest=AbstractTextAndNumberOperationsTest test but the run failed due to a network error while Maven wrapper attempted to download Maven (Network is unreachable).
• No other automated test runs completed in this environment due to the same network restriction.

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Codex Task