DB viewer + query editor enhancements (home-screen-ux-query-editor) (#4)

* feat: add query_history table migration (v5) (Task 1)

* feat: add isDestructiveQuery utility (Task 2)

* feat: add tabType discriminator and openQueryTab to dbViewerStore (Task 3)

* feat: add execute_query command with pagination and query history (Task 4)

* feat: add typed wrappers for executeQuery, getQueryHistory, clearQueryHistory (Task 5)

* fix: global search bypasses folder scope when filters active (Task 6)

* feat: add TagFilterDropdown with checkboxes and empty state (Task 7)

* feat: add DbTypeFilterDropdown with checkboxes and clear all (Task 8)

* feat: wire TagFilterDropdown/DbTypeFilterDropdown into ActionRow, add inline tag creation (Task 9)

* feat: add Name input to GeneralTab for connection editing (Task 10)

* feat: add QueryEditor Monaco wrapper with SQL mode and Cmd+Enter (Task 11)

* feat: add DestructiveQueryDialog with SQL preview and confirmation (Task 12)

* feat: integrate query tabs, Monaco editor, destructive guard into DbViewerScreen (Task 13)

* fix: harden moveConnection against race conditions on rapid drags (Task 14)

* docs: update AGENTS.md implementation status for Home Screen UX + Query Editor (Task 15)

* feat: switch tag filter to OR semantics, add environment filter (F-T16)

* feat: add activeEnvironment filter state to uiStore and useFilteredConnections (F-T17)

* feat: add environment filter select to Filters dropdown (F-T18)

* feat: filter folder cards by tag match or contained connections (F-T19)

* fix: keep grid header width to content, border last column

* fix: hide select-all checkbox and empty-state when no table open

* fix: filter folder cards by any active filter, show global search results (F-T20)

* feat: show 'Showing Search Results' breadcrumb with clear button (F-T21)

* docs: update README + AGENTS.md for Query Editor, filters, and planned AI integration (BYOK)

* feat: refresh indicator with spinning icon and pulse, defer auto-refresh on tab switch

* feat: smart default schema selection, refresh schemas on database switch

* fix: auto-refresh waits for in-flight refresh to complete before next tick

* style: shrink db viewer sidebar nav icons from 20px to 16px

* style: shrink db viewer sidebar nav buttons to 32px (8px padding)

* style: make Tables panel title xs, regular weight, muted

* style: bump Tables panel title back to sm, keep regular weight and muted

* feat: export schema diagram as PNG/JPEG/SVG (entire schema or viewport)

* chore: lockfile for html-to-image

* fix: raise schema visualizer toolbar above legend so export menu isn't hidden

* feat: schema export via save dialog, transparent background option, save notification

* fix: render nothing in tab bar when no tabs are open

* style: reduce tab bar height from 40px to 36px

* style: reduce tab bar height to 32px

* style: revert tab bar height to 36px

* feat: split tab bar with fixed +Query and Changes actions on the right

* style: blue play-icon Query button in tab bar

* refactor: remove sidebar New Query button (now in tab bar)

* style: conditional bottom padding in sidebar toolbar when nothing is below

* feat: distinguish table and query tabs with icons

* style: tab icons follow active/inactive state, muted colors

* feat: query tab toolbar (run/format/dialect badge) + bare transparent editor

* style: blue rounded Run Query button in query toolbar

* feat: smart platform-aware shortcut tooltip on Run Query (⌘+⏎ / Ctrl+Enter)

* style: show only the shortcut in the Run Query tooltip

* fix: Cmd+Enter keybinding stale closure; add run pulse to query toolbar; bundle monaco locally (offline)

* feat: show placeholder text in empty query editor

* feat: SQL autocomplete — keywords + table names from active schema

* feat: per-table column autocomplete on 'table.' + docs update

* feat: query-variant result toolbar — export/refresh/columns left, smart-unit execution time right

* fix: populate execution_time_ms on query results so the toolbar can show time taken

* fix: re-measure monaco fonts after async font load to stop cursor drift

* feat: resizable + collapsible query results panel

* refactor: move results caret onto the resize handle (centered), bottom caret when collapsed

* style: thin drag strip with caret on its own centered pill

* refactor: remove Queue button from table toolbar (Changes lives in tab bar)

* style: changes button becomes bordered rounded icon with count badge

* docs: mark tab-bar Changes queue button in AGENTS.md and README

src/components/folders/FolderBreadcrumb.test.tsx

@@ -34,4 +34,17 @@ describe("FolderBreadcrumb", () => {
     await userEvent.click(screen.getByText("All Connections"));
     expect(fn).toHaveBeenCalledWith(null);
   });
+
+  it("shows 'Showing Search Results' when hasSearch is true", () => {
+    render(<FolderBreadcrumb folders={folders} activeFolderId={null} onNavigate={() => {}} hasSearch />);
+    expect(screen.getByText("Showing Search Results")).toBeInTheDocument();
+    expect(screen.queryByText("All Connections")).not.toBeInTheDocument();
+  });
+
+  it("calls onClearSearch when Clear is clicked", async () => {
+    const fn = vi.fn();
+    render(<FolderBreadcrumb folders={folders} activeFolderId={null} onNavigate={() => {}} hasSearch onClearSearch={fn} />);
+    await userEvent.click(screen.getByText("Clear"));
+    expect(fn).toHaveBeenCalledTimes(1);
+  });
 });

src/components/folders/FolderBreadcrumb.tsx

@@ -1,16 +1,45 @@
 import type { Folder } from "../../lib/types";
-import { ChevronRight, Home } from "lucide-react";
+import { ChevronRight, Home, Search, X } from "lucide-react";
 import { getFolderPath } from "../../lib/utils";
 
 interface FolderBreadcrumbProps {
   folders: Folder[];
   activeFolderId: string | null;
   onNavigate: (folderId: string | null) => void;
+  hasSearch?: boolean;
+  onClearSearch?: () => void;
 }
 
-export function FolderBreadcrumb({ folders, activeFolderId, onNavigate }: FolderBreadcrumbProps) {
+export function FolderBreadcrumb({
+  folders,
+  activeFolderId,
+  onNavigate,
+  hasSearch = false,
+  onClearSearch,
+}: FolderBreadcrumbProps) {
   const path = getFolderPath(folders, activeFolderId);
 
+  if (hasSearch) {
+    return (
+      <nav className="flex items-center gap-1 text-sm text-text-muted">
+        <span className="flex items-center gap-1 px-2 py-1 text-text">
+          <Search size={14} />
+          <span>Showing Search Results</span>
+        </span>
+        {onClearSearch && (
+          <button
+            onClick={onClearSearch}
+            aria-label="Clear search"
+            title="Clear search"
+            className="inline-flex items-center gap-1 px-2 py-1 rounded-md text-text-muted hover:text-text hover:bg-surface-raised transition-colors cursor-pointer"
+          >
+            <X size={14} /> Clear
+          </button>
+        )}
+      </nav>
+    );
+  }
+
   return (
     <nav className="flex items-center gap-1 text-sm text-text-muted">
       <button