🧹 Remove dead code functions across multiple packages

[dsyme]

Summary

• Removes unused functions from permissions_factory.go, frontmatter_types.go, safe_output_parser.go, and js.go
• Updates DEADCODE.md with a structured multi-batch removal plan (batches 5–16) and correct methodology for handling test-only callers
• Clarifies that functions called only in test files are still considered dead in the production binary and should be deleted along with their tests

[Copilot]

Pull request overview

Removes dead/unused Go helper functions across the workflow package and updates the dead-code removal guide to document the correct process and a batch-by-batch plan for future cleanups.

Changes:

• Deleted unused parser/config helper functions in pkg/workflow/safe_output_parser.go and frontmatter extraction wrappers in pkg/workflow/frontmatter_types.go.
• Removed unused permission factory constructors in pkg/workflow/permissions_factory.go and a dead JS getter stub in pkg/workflow/js.go.
• Expanded and corrected DEADCODE.md with methodology, pitfalls, and a structured batch plan/checklist.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/workflow/safe_output_parser.go	Removes unused exported parsing helpers for discussion/close/list configs.
pkg/workflow/permissions_factory.go	Removes unused permission-constructor helpers.
pkg/workflow/js.go	Removes an unused internal JS getter stub.
pkg/workflow/frontmatter_types.go	Removes unused convenience wrappers for string/int extraction.
DEADCODE.md	Adds correct methodology, pitfalls, and a detailed multi-batch removal plan/checklist.

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