feat: restore mentor page to final day/night spec

Rebuild the mentor workspace per the approved final design (day.png/night.png):
- mentorView gets a dedicated full-width immersive shell (independent 56px
  top bar with page title slot + theme mode text, hidden module-nav/market
  tape/overview/status bar) scoped to body[data-active-view=mentorView].
- Assistant messages become borderless body text with name/time above; only
  user messages use a blue bubble; keep loading/error/streaming caret states.
- 4 quick topics stay visible with history; composer restored to a framed
  ~94px card with bottom-left shortcut hint and bottom-right send button.
- Directory tools merged into one row (search + filter menu + sort); the
  filter menu still offers all/A/B/C; list selected state is an inset rounded
  fill; contact rows are borderless 75px items.
- Chat header always shows pin/note/profile/clear; pin reuses /api/mentors/
  preferences; theme toggle stays the single #themeToggle.
- Night tokens match the spec including the two distinct blues (#316FEF link,
  #5B8DEF quote/selected icon). Mobile (<768) stacks panels with no horizontal
  overflow; 1024+ follows the desktop spec.
- Update stale test baselines (300px sidebar, 94px composer, hint presence,
  night bubble color, centered disclaimer) and regenerate the architecture
  inventory.

Co-authored-by: multica-agent <github@multica.ai>

config/architecture-inventory.json

@@ -370,9 +370,9 @@
     }
   ],
   "css_layers": [
-    "/shared/tokens.css?v=20260806-2",
+    "/shared/tokens.css?v=20260818-1",
     "/shared/base.css?v=20260806-1",
-    "/shared/shell.css?v=20260806-2",
+    "/shared/shell.css?v=20260818-1",
     "/shared/auth.css?v=20260806-1",
     "/shared/components/controls.css?v=20260806-1",
     "/shared/components/navigation.css?v=20260806-1",
@@ -390,7 +390,7 @@
     "/pages/popularity/foundation.css?v=20260806-1",
     "/pages/dragon-tiger/foundation.css?v=20260806-1",
     "/pages/screener/foundation.css?v=20260806-2",
-    "/pages/mentor/foundation.css?v=20260806-2",
+    "/pages/mentor/foundation.css?v=20260818-1",
     "/pages/heaven/foundation.css?v=20260806-2",
     "/pages/review/foundation.css?v=20260806-1"
   ],
@@ -451,8 +451,8 @@
     },
     {
       "path": "frontend/shared/shell.css",
-      "bytes": 51978,
-      "lines": 3224
+      "bytes": 54738,
+      "lines": 3348
     },
     {
       "path": "backend/features/heaven/engine.py",
@@ -461,8 +461,8 @@
     },
     {
       "path": "frontend/index.html",
-      "bytes": 45846,
-      "lines": 643
+      "bytes": 46345,
+      "lines": 649
     },
     {
       "path": "backend/features/screener/catalog.py",
@@ -541,8 +541,8 @@
     },
     {
       "path": "frontend/shared/admin.js",
-      "bytes": 13975,
-      "lines": 256
+      "bytes": 14386,
+      "lines": 265
     },
     {
       "path": "backend/features/heaven/market_context.py",
@@ -561,13 +561,13 @@
     },
     {
       "path": "backend/features/system/service.py",
-      "bytes": 12392,
-      "lines": 254
+      "bytes": 12812,
+      "lines": 262
     },
     {
       "path": "backend/features/market/insights_auction.py",
-      "bytes": 10717,
-      "lines": 221
+      "bytes": 11618,
+      "lines": 243
     },
     {
       "path": "backend/features/heaven/readings.py",
@@ -605,14 +605,19 @@
       "lines": 194
     },
     {
-      "path": "backend/features/screener/formula.py",
-      "bytes": 6983,
-      "lines": 146
+      "path": "frontend/pages/mentor/page.html",
+      "bytes": 8199,
+      "lines": 110
     },
     {
       "path": "backend/data/providers/tushare_daily.py",
-      "bytes": 6837,
-      "lines": 160
+      "bytes": 7121,
+      "lines": 167
+    },
+    {
+      "path": "backend/features/screener/formula.py",
+      "bytes": 6983,
+      "lines": 146
     },
     {
       "path": "backend/application.py",
@@ -644,11 +649,6 @@
       "bytes": 6202,
       "lines": 141
     },
-    {
-      "path": "frontend/pages/mentor/page.html",
-      "bytes": 6190,
-      "lines": 89
-    },
     {
       "path": "backend/features/screener/selection.py",
       "bytes": 6092,
@@ -704,6 +704,11 @@
       "bytes": 4276,
       "lines": 91
     },
+    {
+      "path": "frontend/shared/theme.js",
+      "bytes": 4258,
+      "lines": 117
+    },
     {
       "path": "backend/features/screener/engine.py",
       "bytes": 4242,
@@ -714,11 +719,6 @@
       "bytes": 4118,
       "lines": 115
     },
-    {
-      "path": "frontend/shared/theme.js",
-      "bytes": 4118,
-      "lines": 115
-    },
     {
       "path": "frontend/shared/table.js",
       "bytes": 3790,