#600: move quick-note entry from floating side tab into meetings header

User reported the yellow vertical "اكتب ملاحظة…" tab pinned to the page
edge (left-0 top-[40vh]) felt out of place and asked for it to live
inside the Executive Meetings header in a clear spot.

Changes (artifacts/tx-os/src/pages/executive-meetings.tsx):
- Added an amber-tinted Button in the header action cluster, placed
  before the Export PDF button so it reads first in RTL. Uses
  bg-amber-100 / border-amber-300 to keep the original yellow visual
  identity while matching the other header buttons' shape and size.
  Reuses the existing `executiveMeetings.quickNote.label` i18n key —
  no new translations. testid: `em-quick-note-header`.
- Same gating as the old floating tab: section === "schedule" &&
  !isFullscreen && !bulkToolbarActive && !quickNoteOpen, so the button
  hides while the composer is open, in fullscreen, during bulk
  selection, and on non-schedule sub-pages.
- Removed the `<MeetingsQuickNoteTab />` mount and the component
  definition itself. Updated the stale comment on `bulkToolbarActive`
  to refer to the header button.

Verified:
- `rg em-quick-note-tab|MeetingsQuickNoteTab` clean across repo (no
  tests referenced the old testid).
- `pnpm --filter @workspace/tx-os exec tsc --noEmit` clean.

No deviation from the plan.

artifacts/tx-os/src/pages/executive-meetings.tsx

@@ -816,35 +816,6 @@ function HeaderClock({ lang, date }: { lang: "ar" | "en"; date: string }) {
   );
 }
 
-function MeetingsQuickNoteTab({
-  lang,
-  onClick,
-}: {
-  lang: "ar" | "en";
-  onClick: () => void;
-}) {
-  const { t } = useTranslation();
-  const label = t("executiveMeetings.quickNote.label", lang === "ar" ? "اكتب ملاحظة…" : "Take a note…");
-  // Tab sits on the page edge that is visually "left" in LTR and "right"
-  // in RTL — but the spec calls for "left of meetings page", so we pin
-  // to physical left in both directions. Hidden in print.
-  return (
-    <button
-      type="button"
-      onClick={onClick}
-      aria-label={label}
-      title={label}
-      data-testid="em-quick-note-tab"
-      className="flex fixed left-0 top-[40vh] z-30 flex-col items-center justify-center gap-2 w-7 py-3 rounded-r-lg bg-amber-200 hover:bg-amber-300 border border-amber-300 border-l-0 text-[#0B1E3F] shadow-sm transition-all duration-150 hover:translate-x-0.5 print:hidden"
-      style={{ writingMode: "vertical-rl" as const }}
-    >
-      <Plus className="w-4 h-4 rotate-90" aria-hidden="true" />
-      <span className="text-xs font-medium tracking-wide select-none">{label}</span>
-    </button>
-  );
-}
-
-
 function ExecutiveMeetingsPageInner() {
   const { t, i18n } = useTranslation();
   const [, setLocation] = useLocation();
@@ -911,8 +882,8 @@ function ExecutiveMeetingsPageInner() {
 
   // The schedule section publishes whether its bulk-action toolbar is
   // currently visible (≥1 row selected in edit mode) so the page-level
-  // MeetingsQuickNoteTab can step out of the way while the user works
-  // with destructive bulk actions.
+  // quick-note header button can step out of the way while the user
+  // works with destructive bulk actions.
   const [bulkToolbarActive, setBulkToolbarActive] = useState(false);
   useEffect(() => {
     if (section !== "schedule" && bulkToolbarActive) setBulkToolbarActive(false);
@@ -1031,15 +1002,8 @@ function ExecutiveMeetingsPageInner() {
       dir={isRtl ? "rtl" : "ltr"}
       style={{ ["--em-header-h" as string]: "0px", ["--em-heading-h" as string]: "0px" }}
     >
-      {section === "schedule" && !isFullscreen && !bulkToolbarActive && !quickNoteOpen && (
-        <MeetingsQuickNoteTab
-          lang={lang}
-          onClick={() => {
-            setQuickNoteOpen(true);
-            setQuickNoteTrigger((n) => n + 1);
-          }}
-        />
-      )}
+      {/* #600: yellow floating side tab removed — entry point is now
+          the amber "Take a note" button in the header action cluster. */}
       {isFullscreen && (
         <button
           type="button"
@@ -1098,6 +1062,27 @@ function ExecutiveMeetingsPageInner() {
           </div>
 
           <div className="flex items-center gap-2">
+            {/* #600: quick-note entry point moved off the page edge
+                into the header. Same gating as the old floating tab. */}
+            {section === "schedule" && !isFullscreen && !bulkToolbarActive && !quickNoteOpen && (
+              <Button
+                variant="outline"
+                size="sm"
+                className="gap-1.5 bg-amber-100 hover:bg-amber-200 border-amber-300 text-[#0B1E3F]"
+                onClick={() => {
+                  setQuickNoteOpen(true);
+                  setQuickNoteTrigger((n) => n + 1);
+                }}
+                aria-label={t("executiveMeetings.quickNote.label", lang === "ar" ? "اكتب ملاحظة…" : "Take a note…")}
+                title={t("executiveMeetings.quickNote.label", lang === "ar" ? "اكتب ملاحظة…" : "Take a note…")}
+                data-testid="em-quick-note-header"
+              >
+                <Plus className="w-4 h-4" />
+                <span className="hidden sm:inline">
+                  {t("executiveMeetings.quickNote.label", lang === "ar" ? "اكتب ملاحظة…" : "Take a note…")}
+                </span>
+              </Button>
+            )}
             {!isPresidentView && (
               <Button
                 variant="outline"