feat: migrate website-creator from Next.js+Payload to Astro+Tina CMS

Major changes:
- Replace Payload CMS with Tina CMS (self-hosted)
- Add Astro DB for consent logging (PDPA compliant)
- Update Tailwind v3 to v4 (@tailwindcss/vite plugin)
- Add astro-tina-starter template
- Rewrite consent template for Astro (ConsentBanner.astro, Astro DB, Nano Stores)
- Add install-tina-backend.sh for self-hosted Tina per customer
- Rename convert-astro.sh to migrate-tina.sh
- Add AGENTS.md template for generated websites
- Delete all Payload/Next.js files

Technical updates:
- Astro DB using defineDb with eq operators for queries
- Tailwind v4 with @theme block
- Tina CMS local development mode
- Proper Astro API routes for consent

Research-verified with official documentation (April 2026)

skills/website-creator/templates/consent/stores/consent.ts

@@ -0,0 +1,75 @@
+import { map } from 'nanostores';
+
+export interface ConsentState {
+  analytics: boolean;
+  marketing: boolean;
+  functional: boolean;
+  hasConsented: boolean;
+  timestamp?: string;
+}
+
+export interface ConsentLogData extends ConsentState {
+  ip?: string;
+  userAgent?: string;
+}
+
+export const defaultConsent: ConsentState = {
+  analytics: false,
+  marketing: false,
+  functional: false,
+  hasConsented: false,
+};
+
+export const consentStore = map<ConsentState>(defaultConsent);
+export const STORAGE_KEY = 'pdpa_consent';
+
+export function loadConsent(): ConsentState {
+  if (typeof localStorage === 'undefined') {
+    return defaultConsent;
+  }
+
+  const stored = localStorage.getItem(STORAGE_KEY);
+  if (stored) {
+    try {
+      const parsed = JSON.parse(stored) as ConsentState;
+      consentStore.set(parsed);
+      return parsed;
+    } catch {
+      return defaultConsent;
+    }
+  }
+  return defaultConsent;
+}
+
+export function saveConsentLocally(state: ConsentState): void {
+  if (typeof localStorage === 'undefined') return;
+  
+  localStorage.setItem(STORAGE_KEY, JSON.stringify(state));
+  consentStore.set(state);
+}
+
+export function hasAnalyticsConsent(): boolean {
+  const state = consentStore.get();
+  return state.hasConsented && state.analytics;
+}
+
+export function hasMarketingConsent(): boolean {
+  const state = consentStore.get();
+  return state.hasConsented && state.marketing;
+}
+
+export function hasFunctionalConsent(): boolean {
+  const state = consentStore.get();
+  return state.hasConsented;
+}
+
+export function resetConsent(): void {
+  if (typeof localStorage === 'undefined') return;
+  
+  localStorage.removeItem(STORAGE_KEY);
+  consentStore.set(defaultConsent);
+}
+
+export function hasConsented(): boolean {
+  return consentStore.get().hasConsented;
+}