Add nextflow module generate-meta command

[jorgee]

Summary

• Adds nextflow module generate-meta CLI subcommand that parses a module's main.nf and generates a meta.yml template pre-populated with all inferable values
• Supports both V1 (classic qualifier syntax: val, path, tuple) and V2 (static type syntax: reads: Path, (meta, reads): Tuple<String, Path>)
• Implements two-pass static analysis for V2 output type inference: builds a symbol map from input parameters and exec block assignments, then resolves output types via declared type → symbol map lookup → RHS expression inference chain
• Adds -force flag to overwrite an existing meta.yml and -dry-run flag to print to stdout without writing

Changes

• CmdModule.groovy — registers the new generate-meta subcommand
• ModuleGenerateMeta.groovy — CLI entry point with path resolution, overwrite guard, dry-run routing
• MetaYmlGenerator.groovy — AST extraction (V1 + V2) and YAML rendering via SnakeYAML
• MetaYmlGeneratorTest.groovy — 14 Spock unit tests covering V1 qualifiers, V2 typed inputs, symbol map inference, tuple sub-entries, YAML rendering
• ModuleGenerateMetaTest.groovy — 10 Spock CLI tests covering generation, overwrite guard, dry-run, error cases
• VariableScopeVisitor.java — minor related fix

Test plan

• Run ./gradlew :nextflow:test --tests "nextflow.module.MetaYmlGeneratorTest" — all 14 tests pass
• Run ./gradlew :nextflow:test --tests "nextflow.cli.module.ModuleGenerateMetaTest" — CLI tests pass
• Manual: nextflow module generate-meta <module-dir> generates a valid meta.yml
• Manual: re-running without -force errors; with -force regenerates; -dry-run prints to stdout

🤖 Generated with Claude Code