feat(21-02): add skeleton loading states to initiative detail page

Replace plain "Loading initiative..." and "Loading phases..." text with
structured skeleton placeholders matching the page layout: header with
back arrow/title/badge, two-column grid with phase accordions and
sidebar panels.

packages/web/src/routes/initiatives/$id.tsx

@@ -2,6 +2,7 @@ import { useState, useCallback } from "react";
 import { createFileRoute, useNavigate } from "@tanstack/react-router";
 import { AlertCircle } from "lucide-react";
 import { Button } from "@/components/ui/button";
+import { Skeleton } from "@/components/Skeleton";
 import { trpc } from "@/lib/trpc";
 import { InitiativeHeader } from "@/components/InitiativeHeader";
 import { ProgressPanel } from "@/components/ProgressPanel";
@@ -313,8 +314,28 @@ function InitiativeDetailPage() {
   // Loading state
   if (initiativeQuery.isLoading) {
     return (
-      <div className="flex items-center justify-center py-12 text-muted-foreground">
-        Loading initiative...
+      <div className="space-y-6">
+        {/* Header skeleton */}
+        <div className="flex items-center gap-4">
+          <Skeleton className="h-4 w-4" />
+          <Skeleton className="h-7 w-64" />
+          <Skeleton className="h-5 w-20" />
+        </div>
+
+        {/* Two-column grid skeleton */}
+        <div className="grid grid-cols-1 gap-6 lg:grid-cols-[1fr_340px]">
+          {/* Left: phase accordion skeletons */}
+          <div className="space-y-1">
+            <Skeleton className="h-12 w-full rounded border" />
+            <Skeleton className="h-12 w-full rounded border" />
+          </div>
+
+          {/* Right: ProgressPanel + DecisionList skeletons */}
+          <div className="space-y-6">
+            <Skeleton className="h-24 w-full rounded" />
+            <Skeleton className="h-20 w-full rounded" />
+          </div>
+        </div>
       </div>
     );
   }
@@ -381,8 +402,10 @@ function InitiativeDetailPage() {
 
           {/* Phase loading */}
           {phasesQuery.isLoading && (
-            <div className="py-8 text-center text-muted-foreground">
-              Loading phases...
+            <div className="space-y-1 pt-3">
+              {Array.from({ length: 3 }).map((_, i) => (
+                <Skeleton key={i} className="h-10 w-full" />
+              ))}
             </div>
           )}