Play hub + Daily Word game (Phase 1 of the games feature)

A calm /play space — "after the brief, a small thing to enjoy." Framework-ready
for more games (Word Search next; zen/coloring later).

* Daily Word (5 letters / 6 guesses) + Long Word (6 / 7) — same Wordle mechanic,
  Upbeat Bytes flavor (no "Wordle" in the UI). Hopeful answers; after solving, a
  one-line "why this word matters."
* LLM proposes, code disposes: answers are picked deterministically by date-seed
  from a hand-curated hopeful pool that's pre-validated ⊆ the guess dictionary
  (always typeable), avoiding recent repeats; the LLM only adds the optional
  "why" (with fallback). daily_puzzles(date, game, variant, payload) stores them
  so everyone gets the same daily; the cycle pre-generates with the "why".
* Bundled guess dictionaries (words-5/6.json, ~12.6k/22.4k) for client-side guess
  validation — never the LLM. Answer lightly obfuscated (base64) in the payload.
* Private, gentle stats (played/solved/streak, guess distribution); spoiler-free
  emoji-grid share. No leaderboard, no timer, no streak-loss drama.
* Play in the bottom nav (replacing Browse, still on the lane rail) + the header.

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

goodnews/db.py

@@ -260,6 +260,16 @@ CREATE TABLE IF NOT EXISTS feedback_replies (
 );
 CREATE INDEX IF NOT EXISTS idx_feedback_replies_fid ON feedback_replies(feedback_id);
 
+CREATE TABLE IF NOT EXISTS daily_puzzles (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    puzzle_date TEXT NOT NULL,
+    game TEXT NOT NULL,          -- 'word' | 'wordsearch'
+    variant TEXT NOT NULL DEFAULT '',
+    payload_json TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    UNIQUE (puzzle_date, game, variant)
+);
+
 CREATE TABLE IF NOT EXISTS user_follows (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,