feat(kb): drag-to-resize splitter + search survives view switch

Two requests on top of v0.1.9:

1. Drag-to-resize splitter
   The previous fixed Bootstrap col-md-5/col-md-7 split locked the
   user into 41.66% answer / 58.33% PDF. Replaced with a flex-row
   layout containing a 6px drag handle. mousedown spawns a fixed
   transparent overlay so the PDF.js iframe doesn't swallow mouse
   events while dragging; mouseup persists the chosen ratio (clamped
   15-85%) to localStorage as kb-split-pct, so the next page-load and
   the next session both come back to the same layout. Both the
   ask split view and the search split view share _buildSplitShell +
   _wireSplitter — single source of truth for the geometry.

2. Search survives a view switch
   Search had the same view-bound promise problem ask had before
   v0.1.9. Hoisted the in-flight request to a module-level
   _activeSearch and the most recent {query, kind, hits, selectedIdx}
   to _lastSearch + sessionStorage. afterRender restores the input,
   the kind filter, the hit list (with the same hit highlighted), and
   the right-pane preview. Click handler updates selectedIdx so a
   round-trip lands on the user's last-clicked hit, not always on the
   top-ranked one.

The persistence helpers grew a tiny refactor: _loadJson/_saveJson/_clear
replace the ask-only SS_KEY shim and now back both ask + search keys.

Refs Task Master #5, #6

.taskmaster/tasks/tasks.json

@@ -37,6 +37,30 @@
         "dependencies": [],
         "createdAt": "2026-04-25T10:00:00Z"
       },
+      {
+        "id": 5,
+        "title": "feat(kb): drag-to-resize splitter (both ask + search)",
+        "description": "Replace the fixed Bootstrap col-md-5/7 split with a flex layout containing a 6px drag handle. mousedown on the handle starts the drag; while dragging an invisible full-screen overlay covers any iframe so the PDF.js viewer doesn't swallow mouse events. The chosen ratio (15-85%) persists to localStorage as kb-split-pct so the layout sticks across sessions. Both modes share the same _buildSplitShell helper so the look stays consistent.",
+        "status": "done",
+        "priority": "normal",
+        "details": "Default ratio = 42% left (matches the previous col-md-5 ≈ 41.66%). Applied to renderSearchResults, renderAskAnswer, and showSearchPreview (which now uses 100%-height containers via flex column).",
+        "testStrategy": "Open ask mode, drag the divider; verify PDF iframe doesn't lose mouse focus mid-drag; reload — divider stays at last position. Repeat in search mode.",
+        "subtasks": [],
+        "dependencies": [],
+        "createdAt": "2026-04-25T11:00:00Z"
+      },
+      {
+        "id": 6,
+        "title": "fix: search survives view switch (parity with ask in v0.1.9)",
+        "description": "Search mode had the same view-bound promise problem as ask did before v0.1.9: navigating to another EspoCRM screen and back blanked the results. Hoisted {query, kind, promise} to a module-level _activeSearch with the same {query, kind, hits, selectedIdx} sessionStorage replay we already built for ask. Selected hit index also persists so the right pane comes back to the same source/page the user had open.",
+        "status": "done",
+        "priority": "high",
+        "details": "Mirrors the v0.1.9 ask fix in _attachSearchHandlers + afterRender. Click handler updates _lastSearch.selectedIdx so a return-trip lands on the user's last-clicked hit, not always the top-ranked one.",
+        "testStrategy": "Search 'מהי תקנה 37'; click a result other than the first; navigate to Contacts; navigate back — same hit selected, same PDF page on the right.",
+        "subtasks": [],
+        "dependencies": [],
+        "createdAt": "2026-04-25T11:00:00Z"
+      },
       {
         "id": 4,
         "title": "fix: ask survives view switch via module-level promise + sessionStorage",