feat: presence beyond the tab — PWA manifest and the Ghost Log recap

Usability wave Workstream C (#5, #7):
- manifest.webmanifest with existing 192/512/180 icons, linked in
  index.html with theme-color aligned to #07070d; no service worker.
- GET /api/seances/recent: last 12 of the seeker's own séances with
  entity, per-kind event counts (one GROUP BY) and up to 3 spirit
  echoes (one windowed query) — no per-session N+1.
- /log Ghost Log page: cards with GhostGlyph, relative in-fiction
  timestamps, counts and echo lines; LOG link in the séance topbar;
  en/es i18n parity.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/index.html

@@ -5,7 +5,8 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>Quantumancy</title>
     <meta name="description" content="A self-hosted séance. Talk to spirits through your microphone, an RTL-SDR dongle, your network's jitter, your phone's motion sensors, or a text box — a locally-run LLM gives each anomaly a voice." />
-    <meta name="theme-color" content="#0b0a10" />
+    <meta name="theme-color" content="#07070d" />
+    <link rel="manifest" href="/manifest.webmanifest" />
 
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png" />