fix: restore deprecated svcsAnnotationsFile setter and auto-wire task dependencies

[jimisola]

Summary

Fixes #52 and #54.

fix: restore deprecated svcsAnnotationsFile setter (closes #52)

• Adds a deprecated setSvcsAnnotationsFile(Object) setter to RequirementsToolExtension that delegates to svcsAnnotationsFiles.from() and logs a WARN-level deprecation message
• Restores compatibility for builds using the 0.1.0 property name after upgrading to 0.1.1+

feat: auto-wire task dependencies (closes #54)

• assembleRequirements now automatically depends on compileJava and all non-main compileXxxJava tasks (discovered via JavaPlugin in afterEvaluate)
• build is finalized by assembleRequirements — no manual wiring needed in consuming projects
• Adds setSvcsAnnotationsFiles(Object...) setter that replaces auto-discovery with explicit files and disables auto-wired test source set compile dependencies
• Emits a WARN when annotation files are missing at execution time (e.g. when compile was excluded)
• Removes the manual dependsOn/finalizedBy boilerplate from the fixture build.gradle

docs: complete configuration reference

• README updated with a full configuration table, dataset directory reference, auto-wiring explanation, deprecation notice, and task reference section
• Structure aligned with reqstool-java-maven-plugin README

Test plan

• ./gradlew test passes (10 tests including new testSetSvcsAnnotationsFilesMarksExplicit and testDeprecatedSvcsAnnotationsFileSetter)
• Build using old svcsAnnotationsFile = ... syntax succeeds and prints the deprecation warning
• Fresh project with only datasetPath configured: ./gradlew build runs assembleRequirements automatically