feat(app): add Electron desktop UI and evolve memory/retrieval layer

Introduce an Electron app with session browser, memory list, and usage
  views (vanilla JS + Vue scaffolding). On the data layer: add content_type
  and is_meta to messages for transcript control-plane filtering, introduce
  FTS5-backed memory recall with safe tokenization, support memory archival
  via forget() through the renamed --attune runtime, and expose anchors on
  memory records.

app/renderer/styles/sidebar.css

@@ -0,0 +1,74 @@
+.sidebar {
+  border-right: 1px solid var(--hairline-strong);
+  background: rgba(0,0,0,0.2);
+  display: flex; flex-direction: column;
+  min-height: 0;
+}
+.sidebar-brand {
+  display: flex; align-items: center; gap: 8px;
+  padding: 0 14px; height: 36px;
+  border-bottom: 1px solid var(--hairline);
+  flex-shrink: 0;
+}
+.sidebar-brand svg { width: 18px; height: 18px; filter: drop-shadow(0 0 8px rgba(167,139,250,0.4)); }
+.sidebar-brand .name { font-size: var(--text-base); font-weight: 600; color: var(--fg-2); }
+.sidebar-section { padding: 8px 6px; flex-shrink: 0; }
+.sidebar-section.projects { flex: 1; min-height: 0; display: flex; flex-direction: column; padding-bottom: 0; }
+.sidebar-section + .sidebar-section { border-top: 1px solid var(--hairline); }
+.sidebar-section-title {
+  padding: 4px 10px 6px;
+  font-size: 10.5px; color: var(--muted);
+  font-weight: 500; letter-spacing: 0.04em;
+  display: flex; justify-content: space-between;
+  flex-shrink: 0;
+}
+.sidebar-search { position: relative; padding: 0 6px 6px; flex-shrink: 0; }
+.sidebar-search input {
+  width: 100%; height: 24px;
+  padding: 0 8px 0 24px;
+  border: 1px solid var(--hairline); border-radius: 4px;
+  background: var(--surface);
+  font-size: var(--text-sm); color: var(--fg);
+  transition: all 0.1s;
+}
+.sidebar-search input::placeholder { color: var(--muted-2); }
+.sidebar-search input:focus { outline: 0; border-color: var(--accent); background: var(--surface-strong); }
+.sidebar-search-icon {
+  position: absolute; left: 14px; top: 50%; transform: translateY(-50%);
+  width: 11px; height: 11px; color: var(--muted); pointer-events: none;
+}
+.sidebar-list { overflow-y: auto; padding: 2px 0 8px; flex: 1; min-height: 0; }
+.sidebar-item {
+  display: flex; align-items: center; gap: 8px;
+  padding: 0 10px; height: var(--row-h-compact);
+  border-radius: 5px;
+  color: var(--fg-2); font-size: var(--text-base);
+  cursor: pointer; user-select: none;
+  transition: background 0.08s; position: relative;
+  width: 100%; text-align: left;
+}
+.sidebar-item:hover { background: var(--surface-strong); color: var(--fg); }
+.sidebar-item.active { background: var(--accent-soft); color: var(--fg); }
+.sidebar-item.active::before {
+  content: ''; position: absolute; left: -6px; top: 4px; bottom: 4px;
+  width: 2px; background: var(--accent); border-radius: 1px;
+  box-shadow: 0 0 8px var(--accent-glow);
+}
+.sidebar-item .icon { width: 14px; height: 14px; color: var(--muted); flex-shrink: 0; transition: all 0.08s; }
+.sidebar-item.active .icon { color: var(--accent-2); filter: drop-shadow(0 0 4px var(--accent-glow)); }
+.sidebar-item.warning .icon { color: var(--danger); }
+.sidebar-item .label { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.sidebar-item .badge {
+  font-family: var(--font-mono); font-size: 10.5px;
+  color: var(--muted); font-variant-numeric: tabular-nums;
+  line-height: 1; min-width: 22px; text-align: right;
+  flex-shrink: 0; padding: 2px 0;
+}
+.sidebar-item.active .badge { color: var(--fg-2); }
+.sidebar-item.warning .badge {
+  color: var(--danger); background: var(--danger-soft);
+  padding: 2px 6px; border-radius: 8px;
+  margin-right: -6px; min-width: 22px;
+}
+.sidebar-item.sub { padding-left: 30px; height: 26px; font-size: var(--text-sm); }
+.sidebar-item.sub .icon { width: 12px; height: 12px; }