feat(bookslm): v2.2.0 - BooksLM chat AI contextuel par répertoire + 4 providers AI

BooksLM (#76):
- Panneau chat slide-in 450px, clic-droit répertoire → 🧠 BooksLM
- Collecte récursive .md avec limites (200 fichiers, 200K chars)
- Cache SHA-256, redaction secrets, priorité README/index
- SSE streaming, badges sources cliquables, historique localStorage
- Commandes palette: BooksLM ouvrir/nouvelle conversation

Providers AI (4 nouveaux):
- NVIDIA (integrate.api.nvidia.com)
- QwenCloud (dashscope.aliyuncs.com)
- Xiaomi (api.xiaomi.com)
- Mistral (api.mistral.ai)
- Tous OpenAI-compatible, auto-listing modèles

Fix: dropdown config-select suit maintenant le thème (option bg/color)
27 tests BooksLM + 466 tests au total

frontend/style.css

@@ -3833,6 +3833,12 @@ body.resizing-v {
   cursor: pointer;
 }
 
+.config-select option {
+  background: var(--bg-input, #1a1a2e);
+  color: var(--text-primary, #e0e0e0);
+  padding: 4px 8px;
+}
+
 .config-btn-add {
   padding: 8px 16px;
   border: 1px solid var(--accent);
@@ -9006,3 +9012,50 @@ body.popup-mode .content-area {
   color: #f59e0b; font-size: 13px; padding: 8px 12px;
   background: #3a2a1a; border-radius: 6px; margin-top: 8px;
 }
+
+/* ── BooksLM Panel ──────────────────────────────────── */
+.bookslm-panel { position: fixed; right: 0; top: 0; bottom: 0; width: 450px;
+  background: var(--bg, #0d0d1a); border-left: 1px solid var(--border, #333);
+  z-index: 100; display: flex; flex-direction: column;
+  transform: translateX(100%); transition: transform 300ms ease-out;
+  box-shadow: -4px 0 20px rgba(0,0,0,0.3); }
+.bookslm-panel.open { transform: translateX(0); }
+.bookslm-header { display: flex; align-items: center; gap: 8px;
+  padding: 12px 16px; border-bottom: 1px solid var(--border, #333);
+  font-size: 14px; font-weight: 600; }
+.bookslm-header .bookslm-title { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.bookslm-header button { background: none; border: none; cursor: pointer;
+  color: var(--muted, #999); font-size: 16px; padding: 4px 8px; border-radius: 4px; }
+.bookslm-header button:hover { background: var(--surface2, #1e1e3a); color: var(--text, #fff); }
+.bookslm-status { padding: 6px 16px; font-size: 12px; color: var(--muted, #999);
+  border-bottom: 1px solid var(--border, #333); display: flex; gap: 12px; align-items: center; }
+.bookslm-status .bookslm-context-bar { flex: 1; height: 4px; border-radius: 2px;
+  background: var(--surface2, #1e1e3a); overflow: hidden; }
+.bookslm-status .bookslm-context-fill { height: 100%; border-radius: 2px; background: var(--accent, #7C3AED); transition: width 0.3s; }
+.bookslm-messages { flex: 1; overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 12px; }
+.bookslm-bubble { max-width: 85%; padding: 10px 14px; border-radius: 12px; font-size: 14px; line-height: 1.5; word-wrap: break-word; }
+.bookslm-bubble.user { align-self: flex-end; background: var(--accent, #7C3AED); color: #fff; border-bottom-right-radius: 4px; }
+.bookslm-bubble.assistant { align-self: flex-start; background: var(--surface2, #1e1e3a); color: var(--text, #fff); border-bottom-left-radius: 4px; }
+.bookslm-bubble.assistant code { background: rgba(0,0,0,0.2); padding: 1px 4px; border-radius: 3px; font-size: 0.9em; }
+.bookslm-bubble.assistant pre { background: rgba(0,0,0,0.3); padding: 10px; border-radius: 6px; overflow-x: auto; margin: 8px 0; }
+.bookslm-sources { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 8px; }
+.bookslm-source-badge { display: inline-flex; align-items: center; gap: 4px; padding: 2px 8px;
+  background: var(--surface, #16162e); border: 1px solid var(--border, #333); border-radius: 12px;
+  font-size: 11px; color: var(--accent, #7C3AED); cursor: pointer; }
+.bookslm-source-badge:hover { background: var(--surface2, #1e1e3a); }
+.bookslm-input-area { display: flex; gap: 8px; padding: 12px 16px; border-top: 1px solid var(--border, #333); align-items: flex-end; }
+.bookslm-input-area textarea { flex: 1; resize: none; min-height: 36px; max-height: 120px;
+  padding: 8px 12px; border-radius: 8px; border: 1px solid var(--border, #333);
+  background: var(--bg, #0d0d1a); color: var(--text, #fff); font-size: 14px; font-family: inherit; }
+.bookslm-input-area textarea:focus { border-color: var(--accent, #7C3AED); outline: none; }
+.bookslm-input-area button { padding: 8px 16px; border-radius: 8px; border: none;
+  background: var(--accent, #7C3AED); color: #fff; cursor: pointer; font-size: 14px; }
+.bookslm-input-area button:hover { opacity: 0.9; }
+.bookslm-input-area button:disabled { opacity: 0.5; cursor: not-allowed; }
+.bookslm-suggestions { display: flex; flex-direction: column; gap: 6px; padding: 8px 16px 0; }
+.bookslm-suggestion { padding: 8px 12px; border-radius: 8px; border: 1px solid var(--border, #333);
+  background: var(--surface, #16162e); color: var(--muted, #999); cursor: pointer; font-size: 13px; text-align: left; }
+.bookslm-suggestion:hover { background: var(--surface2, #1e1e3a); color: var(--text, #fff); border-color: var(--accent, #7C3AED); }
+@media (max-width: 768px) {
+  .bookslm-panel { width: 100%; }
+}