Add recipe to avoid repeated Pattern.compile calls

[raj7-dev]

What's changed?

Adds a new AvoidRepeatedPatternCompile recipe that moves method-local Pattern.compile() calls with constant regex literals into reusable private static final Pattern fields.

The current implementation:

• Handles Pattern.compile(String) with literal regexes.
• Handles Pattern.compile(String, int) when the flags are constant.
• Does not change dynamically constructed regexes.
• Does not change dynamic flags.
• Uses variable type information when replacing references.
• Handles multiple patterns in the same class.
• Avoids generated field-name collisions.

Unit tests cover both positive and negative cases.

What's your motivation?

Repeatedly calling Pattern.compile() for the same constant regular expression recompiles the regex on each method invocation.

This recipe moves such patterns to reusable class-level constants.

• Fixes Recipe to avoid calling Pattern.compile() too many times #622

Anything in particular you'd like reviewers to focus on?

I'd particularly appreciate feedback on:

• Whether the initial scope of supporting literal regexes is appropriate.
• Whether support for other hard-coded constant expressions should be included in this recipe.
• The generated constant naming strategy.
• Whether there are additional Pattern.compile() cases that should be handled.

Anyone you would like to review specifically?

No specific reviewer.

Have you considered any alternatives or workarounds?

The initial implementation intentionally keeps the detection conservative rather than attempting to evaluate arbitrary expressions.

Dynamic regexes such as:

Pattern.compile(regex);

or:

Pattern.compile(createRegex());

are left unchanged.

This avoids moving expressions to class scope when their value depends on runtime state.

Any additional context

Recipe-specific tests pass locally:

./gradlew test --tests "*AvoidRepeatedPatternCompileTest"

7 tests pass successfully.

I also ran:

./gradlew build

and generated the required recipes.csv entry.

The full repository test suite currently fails locally in unrelated RPC tests. Existing Python tests attempt to install openrewrite==8.90.0, which is unavailable from the configured Python package index.

These failures are unrelated to AvoidRepeatedPatternCompile.

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the [recipe conventions and best practices](https://docs.openrewrite.org/authoring-recipes/recipe-conventions-and-best-practices)
• I've run ./gradlew build locally, and committed any resulting changes to recipes.csv
• I've [formatted the lines I changed](https://github.com/openrewrite/.github/blob/main/CONTRIBUTING.md#code-style-and-formatting), without reformatting code I didn't touch