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/public/manifest.webmanifest

@@ -0,0 +1,29 @@
+{
+  "name": "Quantumancy",
+  "short_name": "Quantumancy",
+  "description": "A self-hosted séance — an instrument for speaking with the dead bandwidth.",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#07070d",
+  "theme_color": "#07070d",
+  "icons": [
+    {
+      "src": "/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png",
+      "purpose": "any"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "any"
+    },
+    {
+      "src": "/apple-touch-icon.png",
+      "sizes": "180x180",
+      "type": "image/png",
+      "purpose": "any"
+    }
+  ]
+}