top bar drag standardization: auto carve-out + the overlay DOM law (owner ruling)

The chains-overlay TopBar had dead drag zones (counts, around search,
close gap) — cause: app-region subtraction resolves by DOM ORDER, not
z-index; the graph chrome's lh-no-drag column came later in the DOM and
punched holes through the overlay's drag band despite sitting visually
underneath (z-40 vs z-10).

Two laws, per the owner's standardization ruling:
- AUTO CARVE-OUT (globals.css): inside any .lh-drag band, every native
  interactive element (button/input/textarea/select/a/summary/
  [contenteditable]) is automatically a no-drag island — draggable
  anywhere that is not a clickable element becomes structural. Manual
  lh-no-drag is only for clickable non-natives.
- THE OVERLAY DOM LAW: a surface containing a TopBar that covers other
  content must be the LAST child of its container — ChainTableOverlay
  moved after the chrome column (verified live: last child, after the
  column; auto-carve rule compiled; search/close/sidebar-toggle all
  still click).

components/top-bar.tsx

@@ -11,17 +11,28 @@
  *
  * Mechanics baked in (the chat-session bar's proven pattern):
  * - h-15 (60px) — matches the sidebar's wordmark band, one border line.
- * - lh-drag — the window-drag band; interactive children carve out with
- *   lh-no-drag (the mask law: carve-outs must come later in the DOM).
+ * - lh-drag — the window-drag band. NATIVE interactive children
+ *   (button/input/a/…) carve out AUTOMATICALLY via the globals.css auto
+ *   carve-out rule (owner standardization ruling, 2026-09-29 night) —
+ *   "draggable anywhere that is not a clickable element" is structural,
+ *   not per-child discipline; manual lh-no-drag is only for clickable
+ *   non-natives (spans/divs with onClick).
  * - select-none — dragging never highlights the title.
  * - SidebarToggle FIRST — the sidebar reopen when closed, with its
  *   Electron traffic-light gutter (lh-closed-toggle).
  * - border-b border-border px-3, gap-3 rhythm.
  *
  * The consumer brings the title (font-title text-3xl tracking-tight) and
- * any right-side controls (lh-no-drag on each). `drag={false}` is the one
- * escape hatch — chat's rename mode (app-region:drag would eat the
- * mousedown that exits the input; owner ask).
+ * any right-side controls. `drag={false}` is the one escape hatch —
+ * chat's rename mode (app-region:drag would eat the mousedown that
+ * exits the input; owner ask).
+ *
+ * THE OVERLAY TWIN OF THE MASK LAW (owner, 2026-09-29 night): app-region
+ * subtraction resolves by DOM order, not z-index — a surface containing
+ * a TopBar that COVERS other content (a full-bleed overlay) must be the
+ * LAST child of its container, or later no-drag elements punch dead
+ * zones through the bar (the chains-overlay bug: the graph chrome's
+ * no-drag column killed drag over the counts/search/close area).
  */
 
 import type { ReactNode } from "react";