Harden java-package validation across distributions

[brunoborges]

Description:
java-package values were interpreted inconsistently across distributions, allowing typos to select a default artifact or fail only after cache or network work. This change introduces one typed capability registry and validates distribution, package, and Temurin JMOD version combinations before installer construction.

The same registry now drives table-based behavior tests and contract checks for action metadata, README guidance, the advanced compatibility table, and E2E package combinations. The published contract includes the JetBrains JCEF and FreeType variants, jdkfile is restricted to jdk, and the generated setup bundle is updated.

Related issue:
Fixes: #1164

Check list:

• Ran npm run check locally (format, lint, build, test) and all checks pass.
• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.

[Copilot]

Pull request overview

This PR centralizes and hardens java-package validation by introducing a single distribution→package capability registry, then using it to validate requested package types (and the Temurin jdk+jmods + version constraint) before installer selection. It also aligns the published action contract (action metadata + docs) and adds contract-style tests to keep docs, metadata, and E2E matrices consistent with the registry.

Changes:

• Add JAVA_PACKAGE_CAPABILITIES + validateJavaPackage() and use it from getJavaDistribution().
• Expand/clarify the published java-package contract in action.yml, README.md, and the advanced compatibility table.
• Add contract and factory tests to ensure docs/metadata/E2E combinations match the registry, and to verify rejection/acceptance behavior.

Show a summary per file

File	Description
src/distributions/package-types.ts	Introduces the typed distribution/package registry and validation logic (including Temurin jdk+jmods version constraint).
src/distributions/distribution-factory.ts	Calls centralized package validation before constructing an installer; removes the previous special-case jdk+jmods check.
README.md	Updates java-package documentation to reflect all supported variants and points readers to the compatibility table.
docs/advanced-usage.md	Updates the package compatibility section wording and clarifies jdkfile validation behavior.
action.yml	Expands the java-package input description to include JetBrains variants and clarifies per-distribution support.
tests/java-package-contract.test.ts	Adds contract tests to keep action.yml, README, advanced docs, and E2E matrices aligned with the registry.
tests/distributors/distribution-factory.test.ts	Adds table-driven acceptance/rejection tests for package validation and Temurin jdk+jmods version gating.
dist/setup/index.js	Updates the bundled distribution output to include the new package-types module and validation behavior.

Review details

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Comments suppressed due to low confidence (1)

tests/java-package-contract.test.ts:72

• The include: matrix parsing assumes distribution values are always single-quoted. YAML allows quoted or unquoted scalars, so this can miss valid entries and silently reduce coverage (future workflow edits could make the test pass while no longer validating all include rows).

    const includedPackages = workflow.matchAll(
      /- distribution: '([^']+)'\s*\n\s*java-package: ([^\s]+)/g
    );

• Files reviewed: 7/8 changed files
• Comments generated: 1
• Review effort level: Low