Aggiunge newsletter custom con D1, double opt-in e invio campagne.

Attiva il form footer, API subscribe/confirm/unsubscribe e endpoint admin protetti, riusando Resend per le email.

Co-authored-by: Cursor <cursoragent@cursor.com>

migrations/0001_newsletter.sql

@@ -0,0 +1,49 @@
+-- Newsletter subscribers and campaign send log
+CREATE TABLE IF NOT EXISTS newsletter_subscribers (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  email TEXT NOT NULL COLLATE NOCASE,
+  status TEXT NOT NULL CHECK (status IN ('pending', 'active', 'unsubscribed')),
+  locale TEXT NOT NULL DEFAULT 'it',
+  confirm_token TEXT,
+  unsubscribe_token TEXT NOT NULL,
+  source TEXT NOT NULL DEFAULT 'footer',
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  confirmed_at TEXT,
+  unsubscribed_at TEXT,
+  UNIQUE (email)
+);
+
+CREATE INDEX IF NOT EXISTS idx_newsletter_subscribers_status
+  ON newsletter_subscribers (status);
+
+CREATE INDEX IF NOT EXISTS idx_newsletter_subscribers_confirm_token
+  ON newsletter_subscribers (confirm_token);
+
+CREATE INDEX IF NOT EXISTS idx_newsletter_subscribers_unsubscribe_token
+  ON newsletter_subscribers (unsubscribe_token);
+
+CREATE TABLE IF NOT EXISTS newsletter_campaigns (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  subject TEXT NOT NULL,
+  body_text TEXT NOT NULL,
+  body_html TEXT,
+  status TEXT NOT NULL DEFAULT 'draft' CHECK (status IN ('draft', 'sending', 'sent', 'failed')),
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  sent_at TEXT,
+  created_by TEXT
+);
+
+CREATE TABLE IF NOT EXISTS newsletter_campaign_sends (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  campaign_id INTEGER NOT NULL,
+  subscriber_id INTEGER NOT NULL,
+  email TEXT NOT NULL,
+  status TEXT NOT NULL CHECK (status IN ('queued', 'sent', 'failed', 'skipped')),
+  error TEXT,
+  sent_at TEXT,
+  FOREIGN KEY (campaign_id) REFERENCES newsletter_campaigns (id),
+  FOREIGN KEY (subscriber_id) REFERENCES newsletter_subscribers (id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_newsletter_campaign_sends_campaign
+  ON newsletter_campaign_sends (campaign_id);