feat(ui): inline expansion for mobile stream entries

Replace bottom-sheet peek with inline accordion at ≤900px.
Entries expand in-place with grid-template-rows animation (0.2s).
Body clamped to 3 lines; fullscreen uncaps it.
Selection toggles DOM classes instead of re-rendering for fluid j/k nav.

web/app.js

@@ -648,6 +648,30 @@
     </div>`;
   }
 
+  function renderInlineDetail(e) {
+    const tags = (e.tags || []).map(t => `<span class="detail-tag">#${t}</span>`).join('');
+    let actions = '';
+    actions += `<button class="action-btn" onclick="event.stopPropagation();nibApp.enterMode('edit')">edit</button>`;
+    if (!e.card_type) {
+      actions += `<button class="action-btn" onclick="event.stopPropagation();nibApp.showAbsorb('${e.id}')">absorb</button>`;
+      actions += `<button class="action-btn primary" onclick="event.stopPropagation();nibApp.showPromote('${e.id}')">promote</button>`;
+    }
+    if (e.card_type) {
+      actions += `<button class="action-btn danger" onclick="event.stopPropagation();nibApp.demoteEntity('${e.id}')">demote</button>`;
+    } else {
+      actions += `<button class="action-btn danger" onclick="event.stopPropagation();nibApp.deleteEntity('${e.id}')">delete</button>`;
+    }
+    return `<div class="exp-inner">
+      <div class="exp-body">${escHtml(e.body || '')}</div>
+      ${tags ? `<div class="exp-tags">${tags}</div>` : ''}
+      <div class="exp-acts">${actions}</div>
+      <div class="exp-toolbar">
+        <button class="peek-mobile-btn" onclick="event.stopPropagation();nibApp.expandInline()">↑</button>
+        <button class="peek-mobile-btn" onclick="event.stopPropagation();nibApp.dismissPeek()">×</button>
+      </div>
+    </div>`;
+  }
+
   function renderEntityItem(e, idx) {
     const glyph = displayGlyph(e);
     const gc = glyphClass(e);
@@ -668,11 +692,18 @@
     }
 
     return `<div class="entity-item${selected}${isCard}" data-index="${idx}" data-id="${e.id}">
+      <div class="entity-head">
         <span class="entity-glyph ${gc}">${glyph}</span>
         ${label}
         ${time}
         <span class="entity-tags">${tags}${cardBadge}</span>
         <span class="entity-meta">${useBadge}</span>
+      </div>
+      <div class="entity-exp">
+        <div class="entity-exp-clip">
+          ${renderInlineDetail(e)}
+        </div>
+      </div>
     </div>`;
   }
 
@@ -694,21 +725,16 @@
 
     pane.classList.add('visible');
 
-    const mobileBar = `<div class="peek-mobile-bar">
-      <button class="peek-mobile-btn" onclick="nibApp.togglePeekFull()">↑</button>
-      <button class="peek-mobile-btn" onclick="nibApp.dismissPeek()">×</button>
-    </div>`;
-
     if (state.peekMode === 'edit') {
-      pane.innerHTML = mobileBar + renderEditMode(e);
+      pane.innerHTML = renderEditMode(e);
     } else if (state.view === 'stream' || !e.card_type) {
-      pane.innerHTML = mobileBar + renderStreamPeek(e);
+      pane.innerHTML = renderStreamPeek(e);
     } else if (state.peekMode === 'run') {
-      pane.innerHTML = mobileBar + renderRunMode(e);
+      pane.innerHTML = renderRunMode(e);
     } else if (state.peekMode === 'fill') {
-      pane.innerHTML = mobileBar + renderFillMode(e);
+      pane.innerHTML = renderFillMode(e);
     } else {
-      pane.innerHTML = mobileBar + renderCardPeek(e);
+      pane.innerHTML = renderCardPeek(e);
     }
 
     bindPeekEvents(e);
@@ -1105,6 +1131,20 @@
   // ========== Actions ==========
 
   function selectEntity(idx) {
+    if (isMobileBreakpoint()) {
+      const prev = state.selectedIndex;
+      if (prev === idx) {
+        state.selectedIndex = -1;
+      } else {
+        state.selectedIndex = idx;
+      }
+      $$('.entity-item.selected').forEach(el => el.classList.remove('selected'));
+      if (state.selectedIndex >= 0) {
+        const target = $(`.entity-item[data-index="${state.selectedIndex}"]`);
+        if (target) target.classList.add('selected');
+      }
+      return;
+    }
     state.selectedIndex = idx;
     state.peekMode = 'preview';
     state.runChecked = new Set();
@@ -1408,13 +1448,31 @@
     },
 
     togglePeekFull() {
+      if (isMobileBreakpoint()) {
+        this.expandInline();
+        return;
+      }
       const pane = $('#detail-pane');
       pane.classList.toggle('peek-full');
       const btn = pane.querySelector('.peek-mobile-btn');
       if (btn) btn.textContent = pane.classList.contains('peek-full') ? '↓' : '↑';
     },
 
+    expandInline() {
+      const sel = $(`.entity-item.selected`);
+      if (!sel) return;
+      sel.classList.toggle('exp-full');
+      const btn = sel.querySelector('.exp-toolbar .peek-mobile-btn');
+      if (btn) btn.textContent = sel.classList.contains('exp-full') ? '↓' : '↑';
+    },
+
     dismissPeek() {
+      if (isMobileBreakpoint()) {
+        const sel = $(`.entity-item.selected`);
+        if (sel) sel.classList.remove('selected', 'exp-full');
+        state.selectedIndex = -1;
+        return;
+      }
       const pane = $('#detail-pane');
       pane.classList.remove('visible', 'peek-full');
       state.selectedIndex = -1;
@@ -1471,6 +1529,14 @@
     }
 
     if (ev.key === 'Escape') {
+      if (isMobileBreakpoint()) {
+        if (state.selectedIndex >= 0) {
+          const sel = $(`.entity-item.selected`);
+          if (sel) sel.classList.remove('selected', 'exp-full');
+          state.selectedIndex = -1;
+          return;
+        }
+      }
       const pane = $('#detail-pane');
       if ($('main').classList.contains('focus-peek')) {
         exitFocusPeek();

web/style.css

@@ -375,28 +375,72 @@ main.focus-peek .resize-handle { visibility: hidden; }
 }
 
 .entity-item {
+    cursor: pointer;
+    border-left: 2px solid transparent;
+    transition: background var(--t-fast), border-left-color var(--t-fast);
+}
+
+.entity-head {
     display: flex;
     align-items: center;
     gap: 8px;
     padding: 5px 16px 5px 20px;
-    cursor: pointer;
-    border-left: 2px solid transparent;
     min-height: 32px;
-    transition: background var(--t-fast), border-left-color var(--t-fast);
 }
 
 .entity-item:hover { background: var(--surf); }
 .entity-item.selected { background: var(--surf); border-left-color: var(--accent); }
 
+.entity-exp { display: none; }
+
+.entity-exp-clip { overflow: hidden; }
+
+.exp-inner {
+    padding: .6rem 1rem .7rem calc(20px + 14px + 8px);
+    border-top: 1px solid var(--border);
+}
+
+.exp-body {
+    font-family: var(--mono);
+    font-size: 11px;
+    color: var(--text);
+    line-height: 1.7;
+    white-space: pre-wrap;
+    word-break: break-word;
+    margin-bottom: .5rem;
+    display: -webkit-box;
+    -webkit-line-clamp: 3;
+    -webkit-box-orient: vertical;
+    overflow: hidden;
+}
+
+.entity-item.exp-full .exp-body {
+    -webkit-line-clamp: unset;
+    overflow: visible;
+}
+
+.exp-tags { display: flex; flex-wrap: wrap; gap: 4px; margin-bottom: .5rem; }
+
+.exp-acts { display: flex; flex-wrap: wrap; gap: 4px; }
+
+.exp-toolbar {
+    display: none;
+    justify-content: space-between;
+    margin-top: .5rem;
+    padding-top: .5rem;
+    border-top: 1px solid var(--border);
+}
+
 .entity-item.is-card {
     background: var(--surf);
     margin: 2px 10px;
     border-radius: var(--r2);
     border: 1px solid var(--border);
     border-left-width: 1px;
-    padding: 7px 12px;
 }
 
+.entity-item.is-card .entity-head { padding: 7px 12px; }
+
 .entity-item.is-card:hover { border-color: var(--muted); }
 .entity-item.is-card.selected { border-color: var(--accent); background: var(--a-bg); }
 
@@ -785,13 +829,6 @@ main.focus-peek .resize-handle { visibility: hidden; }
     overflow: hidden;
 }
 
-.peek-mobile-bar {
-    display: none;
-    justify-content: space-between;
-    padding: 6px 12px;
-    border-bottom: 1px solid var(--border);
-}
-
 .peek-mobile-btn {
     font-family: var(--mono);
     font-size: 14px;
@@ -1488,8 +1525,23 @@ kbd { background: var(--raised); border: 1px solid var(--border); border-radius:
         transition: transform var(--t-base);
         z-index: 50;
     }
-    #detail-pane.visible { transform: translateY(0); }
+    #detail-pane { display: none !important; }
-    #detail-pane.peek-full { height: 100vh; height: 100dvh; top: 0; }
+    .entity-exp {
-    .peek-mobile-bar { display: flex; }
+        display: grid;
+        grid-template-rows: 0fr;
+        transition: grid-template-rows .2s ease;
+    }
+    .entity-item.selected .entity-exp { grid-template-rows: 1fr; }
+    .entity-item.selected .exp-toolbar { display: flex; }
+    .entity-item.exp-full {
+        position: fixed;
+        inset: 0;
+        z-index: 60;
+        background: var(--bg);
+        overflow-y: auto;
+        border-left: none;
+    }
+    .entity-item.exp-full .entity-exp { grid-template-rows: 1fr; }
+    .entity-item.exp-full .exp-inner { padding-top: 1rem; padding-bottom: 2rem; }
     main.focus-peek #entity-panel { display: block; overflow: auto; min-width: 0; }
 }