feat(gallery): promote scaffold gallery to root gallery/ app

[vivek7405]

Problem

The scaffold gallery currently lives inside packages/cli/templates/gallery/ as un-executed template files. Because it is not structured as a top-level runnable app in the monorepo, framework updates cannot easily be validated against the gallery code via webjs check or automated browser tests, leading to template rot and code duplication.

Design / approach

Promote the scaffold gallery to a first-class, top-level application in /gallery at the root of the monorepo (alongside website/):

• gallery/ will serve as a fully functional, live WebJs application deployed at https://gallery.webjs.dev.
• gallery/ becomes the single source of truth for gallery components, feature demos, and example apps.
• packages/cli/lib/create.js and CLI build scripts will source templates directly from /gallery in dev mode.
• Use the established prepack / postpack sync pattern (scripts/sync-scaffold-gallery.mjs, matching sync-scaffold-skill.mjs) to package gallery/ into @webjsdev/cli for npm distribution.
• Remove duplicated static files in packages/cli/templates/gallery/ from git tracking.

Implementation Plan (for the implementing agent)

1. Root Monorepo Structure

• Root package.json: Add "gallery" to the workspaces array. Add top-level helper scripts (dev:gallery, test:browser:gallery).

2. Root gallery/ Application ([NEW])

• Config & Package: gallery/package.json (@webjsdev/gallery), gallery/tsconfig.json, gallery/AGENTS.md, gallery/CONVENTIONS.md.
• App Routes: Move app/features/ (25 single-concept card routes) and app/examples/ (Todo app) from template to gallery/app/. Add root gallery/app/layout.ts and gallery/app/page.ts dashboard.
• Modules & Logic: Move modules/ (domain logic, #db/* sqlite models, auth, todo logic) to gallery/modules/.
• Components & Lib: Move gallery design system (components/ui/) and helper utilities (lib/utils/ui.ts) to gallery/components/ and gallery/lib/.
• Testing: Add unit tests (test/unit/), request pipeline tests (test/auth/), and Web Test Runner browser tests (test/browser/) inside gallery/test/.

3. CLI Packaging & Scaffolding

• scripts/sync-scaffold-gallery.mjs ([NEW]): Prepack script to copy gallery/{app,modules,components,lib,test} into packages/cli/templates/gallery/ during prepack and clean up transient copies during postpack.
• packages/cli/package.json: Wire sync-scaffold-gallery.mjs into prepack and postpack.
• packages/cli/lib/create.js: Update copyGallery() to resolve galleryDir from root gallery/ in monorepo dev mode, falling back to TEMPLATES/gallery in installed npm package mode.
• packages/cli/templates/gallery/: Untrack duplicate static template files in Git.

Invariants & Gotchas to Respect

• Node 24+ & Bun Parity: gallery/ must boot and pass tests on both Node and Bun (bun --bun run dev).
• Convention Checks: webjs check and webjs doctor must pass cleanly for gallery/.
• Offline Scaffolding: prepack must bundle the gallery so npx webjs create continues to work completely offline from npm.

Acceptance criteria

• gallery/ lives at monorepo root as a runnable, testable WebJs application.
• webjs create my-app correctly scaffolds gallery templates sourced from gallery/.
• npx webjs check, npm test, and npm run test:browser run and pass inside gallery/.
• Static redundant files in packages/cli/templates/gallery/ are removed from git tracking and auto-synced via prepack.
• App is ready for production deployment at https://gallery.webjs.dev.
• Tests cover gallery components, server actions, and feature cards across Node and Bun.