Perform code optimization and document cleanup (#1)

## Summary
- add repository-wide quality tooling and verification scaffolding, including CI workflows, pnpm workspace setup, ESLint/Prettier/markdown checks, and generated-output verification helpers
- reorganize skill sources and generation flow by introducing canonical `_source` variants, generator/manifests, reusable helper abstractions, and shared web-automation/browser utilities
- clean up and expand documentation so the root README flows into docs and skill docs, with clearer development, reviewer, installer, and workflow guidance

## Notable changes
- docs flow and consistency cleanup across `README.md`, `docs/README.md`, and related docs
- new scripts for `check`, docs verification, generated-file verification, shell portability, and safe directory replacement
- refactors in Atlassian and web-automation skill runtimes to reduce duplication and centralize reusable code
- changelog, development documentation, and CI surface updates

## Test Plan
- [ ] `pnpm run check`
- [ ] review generated/manifests and skill sync outputs
- [ ] smoke-check docs flow from `README.md` to `docs/README.md` to skill docs

## Notes
- this branch currently includes tracked `skills/web-automation/shared/node_modules` content that should be reviewed carefully as potentially noisy/accidental committed artifacts

Co-authored-by: Stefano Fiorini <stefano.fiorini@firsthorizon.com>
Reviewed-on: #1

.markdownlintignore

@@ -0,0 +1,14 @@
+node_modules/
+**/node_modules/**
+pnpm-lock.yaml
+# Generated agent-variant directories (non-mutating M1 policy)
+skills/atlassian/codex/
+skills/atlassian/claude-code/
+skills/atlassian/cursor/
+skills/atlassian/opencode/
+skills/atlassian/pi/
+skills/web-automation/claude-code/
+skills/web-automation/cursor/
+skills/web-automation/opencode/
+skills/web-automation/pi/
+pi-package/