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>

packages/api/src/router/resource.ts

@@ -291,6 +291,54 @@ export const resourceRouter = createTRPCRouter({
       return { resources, total, page, limit, nextCursor };
     }),
 
+  /** Lightweight resource card for hover tooltips on the timeline. */
+  getHoverCard: protectedProcedure
+    .input(z.object({ id: z.string() }))
+    .query(async ({ ctx, input }) => {
+      const resource = await ctx.db.resource.findUnique({
+        where: { id: input.id },
+        select: {
+          id: true,
+          displayName: true,
+          eid: true,
+          email: true,
+          chapter: true,
+          lcrCents: true,
+          ucrCents: true,
+          currency: true,
+          chargeabilityTarget: true,
+          skills: true,
+          availability: true,
+          isActive: true,
+          areaRole: { select: { id: true, name: true, color: true } },
+          country: { select: { name: true, code: true } },
+          managementLevel: { select: { name: true } },
+          resourceType: true,
+        },
+      });
+      if (!resource) {
+        throw new TRPCError({ code: "NOT_FOUND", message: "Resource not found" });
+      }
+      const directory = await getAnonymizationDirectory(ctx.db);
+      const anon = anonymizeResource(resource, directory);
+      return {
+        id: anon.id,
+        displayName: anon.displayName ?? "",
+        eid: anon.eid ?? "",
+        chapter: resource.chapter,
+        lcrCents: resource.lcrCents,
+        ucrCents: resource.ucrCents,
+        currency: resource.currency,
+        chargeabilityTarget: resource.chargeabilityTarget,
+        skills: resource.skills as Record<string, unknown>[],
+        isActive: resource.isActive,
+        resourceType: resource.resourceType,
+        areaRole: resource.areaRole,
+        country: resource.country,
+        managementLevel: resource.managementLevel,
+      };
+    }),
+
   getById: protectedProcedure
     .input(z.object({ id: z.string() }))
     .query(async ({ ctx, input }) => {