User feedback + expanded privacy-respecting admin stats

Feedback:
- feedback table; POST /api/feedback (anonymous-ok, optional category/email,
  honeypot + per-day flood cap) stores + emails the admin; GET /api/admin/feedback.
- Shared feedback store + FeedbackModal; a speech-bubble opens it from the desktop
  header, the mobile top bar (logo moves left), the footer, and /account. Feedback
  section in /admin.

Stats (additive, same privacy model — no IP/UA/referrer/raw terms):
- Event vocab: summary_viewed (fired on /a load), full_story (card → source),
  not_today/less_like_this/hide_topic, replace_used/replace_none, paywall_replace,
  paywalled_source_open. Card title/image opens /a (no double-count); history
  records via keepalive so it survives the nav.
- Dashboard: Accounts card (counts only), reading funnel (summary→source rate),
  emotional-mix & friction, paywall, returning-visitor buckets. (Health metrics
  deferred to a future monitoring dashboard.) 131 tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

goodnews/db.py

@@ -224,6 +224,21 @@ CREATE TABLE IF NOT EXISTS events (
 CREATE INDEX IF NOT EXISTS idx_events_day ON events(day);
 CREATE INDEX IF NOT EXISTS idx_events_kind ON events(kind);
 CREATE INDEX IF NOT EXISTS idx_events_article ON events(article_id);
+
+-- User feedback (idea / concern / bug / praise). Anonymous-friendly; optional
+-- contact email only if the person wants a reply. visitor_hash is for rate-limit
+-- only (the same hashed anonymous token used by analytics).
+CREATE TABLE IF NOT EXISTS feedback (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    category TEXT NOT NULL DEFAULT 'other',
+    message TEXT NOT NULL,
+    contact_email TEXT,
+    user_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+    visitor_hash TEXT NOT NULL DEFAULT '',
+    day TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+CREATE INDEX IF NOT EXISTS idx_feedback_created ON feedback(created_at);
 """