feat: build Core Design System Portal foundation

[jaavid]

Closes #7

What changed

• builds a product-oriented Storybook landing page
• turns Foundations into canonical runtime documentation for brand, color, typography, icons, spacing, shape, bidi and themes
• adds exact source/revision evidence for Product Planning tokens
• renders light/dark and Persian RTL/English LTR examples from exported semantic tokens
• aligns the Storybook manager theme with canonical Core Blue, surfaces, borders and 8px radius
• adds deterministic portal navigation without redefining canonical product meaning

Canonical evidence

• source: CoreLinkPlatform/product-planning/design/tokens.json
• accepted revision: 069baefa4616b6b590ecde55fa09e99db124a148
• schema version: 1.1
• runtime package: @corelinkplatform/design-system@0.1.0-alpha.4

Validation

• CI / typecheck / tests
• Storybook static build
• Cloudflare Pages preview and visual review

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[cloudflare-workers-and-pages]

Deploying design-system with    Cloudflare Pages

Latest commit:	cbac6c6
Status:	✅  Deploy successful!
Preview URL:	https://514c4d60.design-system-dby.pages.dev
Branch Preview URL:	https://feat-core-design-system-port.design-system-dby.pages.dev

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