feat: integrate marked markdown renderer into dashboard build

[chriswritescode-dev]

Summary

Integrates the marked markdown parser (v12.0.2) into the forge dashboard
build pipeline and refactors loop detail rendering with improved data helpers.

Changes

Added

• src/dashboard/marked.min.js — vendored marked library (MIT License)
• src/dashboard/marked-source.ts — auto-generated TypeScript wrapper embedding
  the minified library as a string constant for runtime injection
• Build step in scripts/build.ts that generates marked-source.ts from
  marked.min.js at compile time (ensures proper JS string escaping)

Updated

• src/dashboard/render.ts — extended with data helpers and testable utilities;
  simplified render logic for maintainability
• scripts/build.ts — added marked-source generation stage
• package.json / src/version.ts — version bump 0.4.15 → 0.4.16

Tests

• Preexisting test coverage for the data helpers from the prior refactor commit
  (8b175eb)

Breaking changes

None.