feat: timeline multi-select, demand popover, resource hover card, merged tooltips, dark mode fixes

Major timeline enhancements:
- Right-click drag multi-selection with floating action bar (batch delete/assign)
- DemandPopover for demand strip details (replaces broken "Loading" modal)
- ResourceHoverCard on name hover showing skills, rates, role, chapter
- Merged heatmap+vacation tooltips into unified TimelineTooltip component
- Fixed overbooking blink animation (date normalization, z-index ordering)
- Fixed dark mode sticky column bleed-through in project view
- System roles admin page, notification task management, performance review docs

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/src/components/staffing/StaffingPanel.tsx

@@ -8,10 +8,14 @@ import { InfoTooltip } from "~/components/ui/InfoTooltip.js";
 
 export function StaffingPanel() {
   const [requiredSkills, setRequiredSkills] = useState<string[]>(["TypeScript", "React"]);
-  const [startDate, setStartDate] = useState(new Date().toISOString().split("T")[0] ?? "");
-  const [endDate, setEndDate] = useState(
-    new Date(Date.now() + 90 * 24 * 60 * 60 * 1000).toISOString().split("T")[0] ?? "",
-  );
+  const [startDate, setStartDate] = useState(() => {
+    const d = new Date();
+    return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}-${String(d.getDate()).padStart(2, "0")}`;
+  });
+  const [endDate, setEndDate] = useState(() => {
+    const d = new Date(Date.now() + 90 * 24 * 60 * 60 * 1000);
+    return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}-${String(d.getDate()).padStart(2, "0")}`;
+  });
   const [hoursPerDay, setHoursPerDay] = useState(8);
   const [submitted, setSubmitted] = useState(false);