refactor: replace prepublishOnly with explicit publish workflow

[roottool]

Summary

Replace prepublishOnly script with explicit prepare:publish command and move publishing documentation to docs/PUBLISHING.md to align with the library's design principles.

Changes

Code Changes

• package.json: Replace prepublishOnly with prepare:publish script
• publish.yml: Add explicit validation step using prepare:publish

Documentation Changes

• docs/PUBLISHING.md (new): Publishing guide for maintainers
  • Local validation instructions
  • Workflow overview
  • Design rationale for removing prepublishOnly
• CONTRIBUTING.md: Remove Publishing Process section (moved to docs/)
• README.md: Add Contributing section with links to CONTRIBUTING.md and docs/PUBLISHING.md

Rationale

prepublishOnly violated the explicit over implicit principle by running automatically during npm publish. The new workflow:

• ✅ Declares all validation steps explicitly in the workflow file
• ✅ Ensures transparency and traceability
• ✅ Aligns with "security over convenience" and "no silent fixes" principles
• ✅ Separates contributor documentation (CONTRIBUTING.md) from maintainer documentation (docs/)

Design Principles Alignment

Principle	Implementation
Explicit over implicit	prepare:publish is called explicitly, not triggered automatically
Security over convenience	All validation steps are visible and traceable
Boundary-focused	Clear separation between development and publishing processes
No silent fixes	No hidden automation; every step is declared

Test Plan

• Local validation: bun run prepare:publish succeeds
• Workflow syntax: gh workflow view publish.yml passes
• Pre-commit hooks: lint, format pass
• Pre-push hooks: type check, tests pass (100% coverage)

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (97ad436) to head (41dd911).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #46   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines           22        22           
  Branches         6         6           
=========================================
  Hits            22        22           

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