refactor(docs): consolidate scaffolding/ into guides/

The docs/scaffolding/ directory held two how-to guides (core-package
+ core-ui-component generator references). Both are operationally
identical in shape to docs/guides/scaffolding-a-feature.md — they
just live in a separate top-level docs directory. Consolidating
removes one directory + makes the three scaffolding guides
discoverable as siblings.

Moves (via git mv to preserve history):
  docs/scaffolding/core-package-generator.md
    -> docs/guides/scaffolding-core-package.md
  docs/scaffolding/core-ui-component-generator.md
    -> docs/guides/scaffolding-core-ui-component.md

Empty docs/scaffolding/ directory removed.

AGENTS.md (only consumer of the old paths) updated to point at the
new locations.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -113,8 +113,8 @@ pnpm typecheck         # Type-check all packages
 pnpm lint              # Lint all packages (ESLint boundaries enforced)
 pnpm turbo boundaries  # Validate workspace dependency graph (Turbo boundaries)
 pnpm turbo gen feature       # Scaffold a new feature package (see docs/guides/scaffolding-a-feature.md)
-pnpm turbo gen core-package  # Scaffold an optional core package back (realtime, events, trpc, ui — see docs/scaffolding/core-package-generator.md)
-pnpm turbo gen core-ui-component  # Scaffold a core-ui atomic-design component (atom/molecule/organism — see docs/scaffolding/core-ui-component-generator.md)
+pnpm turbo gen core-package  # Scaffold an optional core package back (realtime, events, trpc, ui — see docs/guides/scaffolding-core-package.md)
+pnpm turbo gen core-ui-component  # Scaffold a core-ui atomic-design component (atom/molecule/organism — see docs/guides/scaffolding-core-ui-component.md)
 pnpm test              # Run all unit + integration tests (Vitest)
 pnpm test:e2e          # Run e2e tests (Playwright across both apps)
 pnpm build             # Build all packages (Turborepo)