Exclude generated sources in build directory from parsing

[timtebeek]

• Fixes Generated kotlin sources inside the build directory are showing up in recipe results #216.

Summary

• Source directories inside the build directory (e.g. protobuf-generated Kotlin sources) are now filtered out at the directory level before file walking, preventing generated sources from being parsed and appearing in recipe results
• Type information from generated sources remains available via compiled class files already on the classpath
• Removed the hardcoded /protos/build/generated exclusion, now covered by the generic build directory filter
• Consolidated duplicated isExcluded/buildDir filtering from individual parse methods (parseJavaFiles, parseKotlinFiles, inline Groovy/multiplatform blocks) into a single filter at the stream assembly point, in both DefaultProjectParser and AndroidProjectParser

Test plan

• Existing tests pass (./gradlew :plugin:test)

[shanman190]

Just curious, but should isExcluded be extracted from each individual parse chain and moved toward the end of all parsing to eject any file that happens to be explicitly excluded?

[timtebeek]

Good suggestion! Extracted the isExcluded/buildDir filtering from each individual parse method (parseJavaFiles(), parseKotlinFiles(), inline Groovy block, and multiplatform Kotlin block) into a single filter applied at the stream assembly point. This applies to both DefaultProjectParser and AndroidProjectParser.