feat: poker session history — browse, delete, and Lyra lookup

Answers three gaps: no way to delete a single poker session (only clear_all),
no way to browse past sessions, and Lyra could only see aggregate stats.

- poker.list_sessions() (per-session summary + hand count + recap flag) and
  poker.delete_session() (removes a session + its hands/reads/observations/
  stacks/rituals; keeps the persistent villain file).
- /history page (date, stakes, venue, net, hours, recap link, per-row delete with
  confirm) + /history/data + DELETE /history/{id}. Nav links from chat + HUD.
- recent_sessions read tool, added to the shared lookups so Lyra can answer
  "how'd my last few sessions go?" in either mode.
- Delete is UI/CLI only — deliberately not a Lyra tool.
- test_modes.py +2 (list/delete, recent_sessions); 44 green.

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

lyra/web/static/index.html

@@ -40,6 +40,7 @@
     <div class="mobile-menu-section">
       <h4>Actions</h4>
       <button id="mobileSessionBtn">🎬 Session HUD</button>
+      <button id="mobileHistoryBtn">📚 Past Sessions</button>
       <button id="mobileThinkingStreamBtn">📜 Live Log (inline)</button>
       <button id="mobileFullLogBtn">⛶ Full Log</button>
       <button id="mobileJournalBtn">📔 Journal</button>
@@ -81,6 +82,7 @@
       <button id="thinkingStreamBtn" title="Show live activity log">📜 Live Log</button>
       <a id="fullLogBtn" href="/logs" target="_blank" rel="noopener" title="Open the full-page log" role="button">⛶ Full Log</a>
       <a id="sessionBtn" href="/session" target="_blank" rel="noopener" title="Live session HUD" role="button">🎬 Session</a>
+      <a id="historyBtn" href="/history" target="_blank" rel="noopener" title="Past sessions" role="button">📚 Sessions</a>
       <a id="mindBtn" href="/self" target="_blank" rel="noopener" title="Read her mind — Lyra's current self-state" role="button">🧠 Mind</a>
       <a id="handsBtn" href="/hands" target="_blank" rel="noopener" title="Recorded poker hands" role="button">🃏 Hands</a>
     </div>
@@ -1081,6 +1083,9 @@
       document.getElementById("mobileSessionBtn").addEventListener("click", () => {
         closeMobileMenu(); window.location.href = "/session";
       });
+      document.getElementById("mobileHistoryBtn").addEventListener("click", () => {
+        closeMobileMenu(); window.location.href = "/history";
+      });
 
       // Connect to the global live log on page load.
       connectThinkingStream();