feat: make the Ghost Log actually do something

It was read-only: one link on the whole page ("back to séance"), no way
to get from "I talked to this spirit" to anything about them. Fixed with
three additions, all client-side against data already fetched in one
call — no backend change:

- Every entity glyph and name links straight to its Codex page.
- Echoes past the first are collapsed behind a "+N more" toggle instead
  of always showing up to 3 — a card reads cleanly at a glance, with
  detail one tap away.
- A channel filter (only shown once >1 mode is actually present in the
  log) so a seeker with a long history can find "just the radio nights."

Deliberately did NOT add a "revisit this spirit" button. Contact is a
probabilistic channel draw (RETURN_CHANCE), not "resume this entity" —
a button that just navigated to /seance would be indistinguishable from
the existing back link and would imply a guarantee the app doesn't make.
Cosmetic interactivity isn't worth shipping.

6 new tests. 372 frontend tests pass total; i18n parity holds.

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

frontend/src/pages/GhostLogPage.css

@@ -79,6 +79,16 @@
   flex: 0 0 auto;
 }
 
+a.ghostlog-glyph {
+  border-radius: 50%;
+  transition: filter 140ms ease;
+}
+
+a.ghostlog-glyph:hover,
+a.ghostlog-glyph:focus-visible {
+  filter: drop-shadow(0 0 8px rgba(124, 255, 178, 0.6));
+}
+
 .ghostlog-body {
   min-width: 0;
   flex: 1;
@@ -91,6 +101,26 @@
   gap: 0.5rem;
 }
 
+.ghostlog-who-link {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: baseline;
+  gap: 0.5rem;
+  text-decoration: none;
+  border-radius: 3px;
+  transition: text-shadow 140ms ease;
+}
+
+.ghostlog-who-link:hover .ghostlog-name,
+.ghostlog-who-link:focus-visible .ghostlog-name {
+  text-shadow: 0 0 10px rgba(124, 255, 178, 0.6);
+}
+
+.ghostlog-who-link:focus-visible {
+  outline: 1px solid #7cffb2;
+  outline-offset: 3px;
+}
+
 .ghostlog-name {
   font-family: Cinzel, serif;
   font-size: 1rem;
@@ -130,6 +160,56 @@
   overflow-wrap: break-word;
 }
 
+.ghostlog-expand {
+  background: transparent;
+  border: none;
+  color: #b26bff;
+  font-family: 'IBM Plex Mono', monospace;
+  font-size: 0.68rem;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+  padding: 0.3rem 0 0.1rem;
+  cursor: pointer;
+  min-height: 32px;
+}
+
+.ghostlog-expand:hover,
+.ghostlog-expand:focus-visible {
+  text-shadow: 0 0 8px rgba(178, 107, 255, 0.6);
+}
+
+.ghostlog-filters {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.4rem;
+  margin: 0 0 1.1rem;
+}
+
+.ghostlog-filter {
+  background: transparent;
+  border: 1px solid rgba(124, 255, 178, 0.25);
+  border-radius: 3px;
+  color: rgba(211, 233, 219, 0.6);
+  font-family: 'IBM Plex Mono', monospace;
+  font-size: 0.72rem;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+  padding: 0.4rem 0.7rem;
+  min-height: 36px;
+  cursor: pointer;
+  transition: color 140ms ease, border-color 140ms ease, background 140ms ease;
+}
+
+.ghostlog-filter:hover {
+  color: #7cffb2;
+}
+
+.ghostlog-filter.active {
+  color: #7cffb2;
+  border-color: rgba(124, 255, 178, 0.6);
+  background: rgba(124, 255, 178, 0.08);
+}
+
 /* phone widths */
 @media (max-width: 420px) {
   .ghostlog-page {