feat(monorepo)!: Migrate CDGPlayer to an Nx package-first workspace

[cutterbl]

Removes the legacy top-level src/, scripts demo assets, and /docs documentation tree in favor of package entrypoints and Storybook-composed documentation.

• chore: Update monorepo tooling and CI workflows
• fix: Resolve build blockers and rename contribution doc
• feat: expand test coverage and enforce per-project CI thresholds
• chore: Stabilize typecheck outputs and test typings
• feat(controls): Refine key labels and settings panel sizing
• chore: Add package readmes and refine coverage/docs reporting
• chore: Tighten lint rules and clean demo/test warnings
• feat(release)!: Prepare the next major package-first release

• migrate CDGPlayer to an Nx package-first workspace
• align package metadata and release automation around scoped
  package entrypoints
• tighten CI validation, coverage thresholds, docs checks, and
  repository ownership
• refine framework-agnostic controls and move framework demo
  settings into anchored popovers
• update demo iconography and supporting Storybook/docs guidance

BREAKING CHANGE: CDGPlayer now publishes from a package-first Nx
workspace.

The legacy top-level source and docs layout is no longer the
published integration surface; consumers should use the scoped
package entrypoints (@cxing/logger, @cxing/cdg-core,
@cxing/cdg-loader, @cxing/cdg-player, and @cxing/cdg-controls).

The release, documentation, CI, and demo/control integration
flows have changed since v0.1.17 and should be reviewed before
upgrading.

[github-actions]

Coverage Summary

Status	Project	Statements	Branches	Functions	Lines
🟢	apps/demo	98.73%	86.99%	100.00%	98.72%
🟢	apps/framework-demo	92.76%	82.42%	100.00%	92.66%
🟢	packages/cdg-controls	98.14%	89.74%	98.11%	98.14%
🟢	packages/cdg-core	98.57%	90.91%	98.39%	98.80%
🟢	packages/cdg-loader	97.78%	86.21%	100.00%	97.74%
🟢	packages/cdg-player	98.94%	90.65%	100.00%	98.93%
🟢	packages/logger	95.56%	88.89%	100.00%	95.12%
	Overall	97.41%	87.19%	99.41%	97.42%

Generated from 7 coverage-summary.json files.