feat(10-01): add SkillCard component, tests, route wiring, and design guide entry

- Create SkillCard.tsx with 3-row layout per UI-SPEC (name link, description, source/rating/actions)
- Create SkillCard.test.tsx with 8 passing unit tests using renderToStaticMarkup
- Create SkillBrowser.tsx and SkillDetail.tsx stub pages
- Update App.tsx: remove CompanySkills import, add skills and skills/detail/:skillId routes
- Add SkillCard to DesignGuide.tsx with 4 variants (default, installed, update available, loading)

ui/src/App.tsx

@@ -26,7 +26,8 @@ import { Costs } from "./pages/Costs";
 import { Activity } from "./pages/Activity";
 import { Inbox } from "./pages/Inbox";
 import { CompanySettings } from "./pages/CompanySettings";
-import { CompanySkills } from "./pages/CompanySkills";
+import { SkillBrowser } from "./pages/SkillBrowser";
+import { SkillDetail } from "./pages/SkillDetail";
 import { CompanyExport } from "./pages/CompanyExport";
 import { CompanyImport } from "./pages/CompanyImport";
 import { DesignGuide } from "./pages/DesignGuide";
@@ -127,7 +128,8 @@ function boardRoutes() {
       <Route path="company/settings" element={<CompanySettings />} />
       <Route path="company/export/*" element={<CompanyExport />} />
       <Route path="company/import" element={<CompanyImport />} />
-      <Route path="skills/*" element={<CompanySkills />} />
+      <Route path="skills" element={<SkillBrowser />} />
+      <Route path="skills/detail/:skillId" element={<SkillDetail />} />
       <Route path="settings" element={<LegacySettingsRedirect />} />
       <Route path="settings/*" element={<LegacySettingsRedirect />} />
       <Route path="plugins/:pluginId" element={<PluginPage />} />

ui/src/components/SkillCard.test.tsx

@@ -0,0 +1,78 @@
+// @vitest-environment node
+
+import { describe, expect, it, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+import { SkillCard } from "./SkillCard";
+import type { SkillListItem } from "../api/skillRegistry";
+
+// Stub @/lib/router Link as an <a> tag for SSR
+vi.mock("@/lib/router", () => ({
+  Link: ({ to, children, ...props }: { to: string; children: React.ReactNode; [key: string]: unknown }) =>
+    <a href={to as string} {...props}>{children}</a>,
+}));
+
+const mockSkill: SkillListItem = {
+  id: "test-source/test-skill",
+  name: "Test Skill",
+  description: "A test skill for unit testing",
+  sourceId: "test-source",
+  category: "testing",
+  activeVersionId: null,
+  removedAt: null,
+  averageRating: 4.2,
+  ratingCount: 10,
+};
+
+describe("SkillCard", () => {
+  it("renders skill name as a link", () => {
+    const html = renderToStaticMarkup(<SkillCard skill={mockSkill} />);
+    expect(html).toContain("Test Skill");
+    expect(html).toContain("skills/detail/");
+  });
+
+  it("renders source badge", () => {
+    const html = renderToStaticMarkup(<SkillCard skill={mockSkill} />);
+    expect(html).toContain("test-source");
+  });
+
+  it("renders star rating when averageRating is non-null", () => {
+    const html = renderToStaticMarkup(<SkillCard skill={mockSkill} />);
+    expect(html).toContain("4.2");
+  });
+
+  it("shows Install skill button when not installed", () => {
+    const html = renderToStaticMarkup(
+      <SkillCard skill={mockSkill} onInstall={() => {}} />,
+    );
+    expect(html).toContain("Install skill");
+  });
+
+  it("shows Update skill button when installed with update", () => {
+    const html = renderToStaticMarkup(
+      <SkillCard skill={mockSkill} isInstalled hasUpdate onUpdate={() => {}} />,
+    );
+    expect(html).toContain("Update skill");
+  });
+
+  it("shows update badge when hasUpdate is true", () => {
+    const html = renderToStaticMarkup(
+      <SkillCard skill={mockSkill} isInstalled hasUpdate onUpdate={() => {}} />,
+    );
+    expect(html).toContain("Update");
+    expect(html).toContain("amber");
+  });
+
+  it("shows check icon when installed without update", () => {
+    const html = renderToStaticMarkup(
+      <SkillCard skill={mockSkill} isInstalled />,
+    );
+    expect(html).toContain("Installed");
+  });
+
+  it("shows loading state on install button", () => {
+    const html = renderToStaticMarkup(
+      <SkillCard skill={mockSkill} onInstall={() => {}} isLoading />,
+    );
+    expect(html).toContain("Installing");
+  });
+});

ui/src/components/SkillCard.tsx

@@ -0,0 +1,127 @@
+import { Check, Download, RotateCcw, Star } from "lucide-react";
+import { Link } from "@/lib/router";
+import { cn } from "@/lib/utils";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Card, CardContent } from "@/components/ui/card";
+import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
+import type { SkillListItem } from "@/api/skillRegistry";
+
+// TODO: hasUpdate detection requires backend enhancement — SkillListItem needs
+// a hasUpdate field or the UI needs to compare activeVersionId against latest version.
+// For now, hasUpdate is always passed as false from parent components.
+
+export interface SkillCardProps {
+  skill: SkillListItem;
+  isInstalled?: boolean;
+  hasUpdate?: boolean;
+  onInstall?: () => void;
+  onUpdate?: () => void;
+  onRollback?: () => void;
+  onUninstall?: () => void;
+  isLoading?: boolean;
+  className?: string;
+}
+
+export function SkillCard({
+  skill,
+  isInstalled = false,
+  hasUpdate = false,
+  onInstall,
+  onUpdate,
+  onRollback,
+  onUninstall,
+  isLoading = false,
+  className,
+}: SkillCardProps) {
+  return (
+    <Card className={cn("flex flex-col", className)}>
+      <CardContent className="p-4 flex flex-col gap-2">
+
+        {/* Row 1: name link (primary visual anchor) + update badge */}
+        <div className="flex items-start justify-between gap-2">
+          <Link
+            to={`/skills/detail/${encodeURIComponent(skill.id)}`}
+            className="text-sm font-medium hover:underline"
+          >
+            {skill.name}
+          </Link>
+          {hasUpdate && (
+            <Badge
+              variant="outline"
+              className="text-xs text-amber-600 border-amber-500 shrink-0"
+              aria-label="Update available"
+            >
+              Update
+            </Badge>
+          )}
+        </div>
+
+        {/* Row 2: description (2-line clamp) */}
+        {skill.description && (
+          <p className="text-xs text-muted-foreground line-clamp-2">{skill.description}</p>
+        )}
+
+        {/* Row 3: source badge + rating + actions (push right) */}
+        <div className="flex items-center gap-2 mt-auto pt-2">
+          <Badge variant="secondary" className="text-xs">{skill.sourceId}</Badge>
+          {skill.averageRating != null && (
+            <span className="flex items-center gap-1 text-xs text-muted-foreground">
+              <Star className="h-3 w-3 fill-amber-400 text-amber-400" />
+              {skill.averageRating.toFixed(1)}
+            </span>
+          )}
+          <div className="ml-auto flex gap-1">
+            {isInstalled && onRollback && (
+              <Tooltip>
+                <TooltipTrigger asChild>
+                  <Button
+                    size="icon-sm"
+                    variant="ghost"
+                    onClick={onRollback}
+                    disabled={isLoading}
+                  >
+                    <RotateCcw className="h-3.5 w-3.5" />
+                  </Button>
+                </TooltipTrigger>
+                <TooltipContent>Rollback</TooltipContent>
+              </Tooltip>
+            )}
+            {!isInstalled && (
+              <Button
+                size="sm"
+                variant="outline"
+                onClick={onInstall}
+                disabled={isLoading}
+              >
+                <Download className="h-3.5 w-3.5 mr-1" />
+                {isLoading ? "Installing\u2026" : "Install skill"}
+              </Button>
+            )}
+            {isInstalled && hasUpdate && (
+              <Button
+                size="sm"
+                variant="outline"
+                onClick={onUpdate}
+                disabled={isLoading}
+              >
+                {isLoading ? "Updating\u2026" : "Update skill"}
+              </Button>
+            )}
+            {isInstalled && !hasUpdate && (
+              <Button
+                size="icon-sm"
+                variant="ghost"
+                disabled
+                title="Installed"
+              >
+                <Check className="h-3.5 w-3.5 text-muted-foreground" />
+              </Button>
+            )}
+          </div>
+        </div>
+
+      </CardContent>
+    </Card>
+  );
+}

ui/src/pages/DesignGuide.tsx

@@ -124,6 +124,7 @@ import { FilterBar, type FilterValue } from "@/components/FilterBar";
 import { InlineEditor } from "@/components/InlineEditor";
 import { PageSkeleton } from "@/components/PageSkeleton";
 import { Identity } from "@/components/Identity";
+import { SkillCard } from "@/components/SkillCard";
 
 /* ------------------------------------------------------------------ */
 /*  Section wrapper                                                    */
@@ -1254,6 +1255,76 @@ export function DesignGuide() {
         </SubSection>
       </Section>
 
+      {/* ============================================================ */}
+      {/*  SKILL CARD                                                   */}
+      {/* ============================================================ */}
+      <Section title="Skill Card">
+        <SubSection title="Variants">
+          <div className="grid grid-cols-1 sm:grid-cols-2 gap-4">
+            <SkillCard
+              skill={{
+                id: "anthropic/code-review",
+                name: "Code Review",
+                description: "Automated code review with style, security, and correctness checks.",
+                sourceId: "anthropic",
+                category: "engineering",
+                activeVersionId: null,
+                removedAt: null,
+                averageRating: 4.7,
+                ratingCount: 42,
+              }}
+              onInstall={() => {}}
+            />
+            <SkillCard
+              skill={{
+                id: "anthropic/planning",
+                name: "Planning",
+                description: "Breaks down complex features into actionable tasks.",
+                sourceId: "anthropic",
+                category: "productivity",
+                activeVersionId: "v1.0.0",
+                removedAt: null,
+                averageRating: null,
+                ratingCount: null,
+              }}
+              isInstalled
+            />
+            <SkillCard
+              skill={{
+                id: "community/docs-writer",
+                name: "Docs Writer",
+                description: "Generates clear technical documentation from code and comments.",
+                sourceId: "community",
+                category: "docs",
+                activeVersionId: "v1.1.0",
+                removedAt: null,
+                averageRating: 3.9,
+                ratingCount: 15,
+              }}
+              isInstalled
+              hasUpdate
+              onUpdate={() => {}}
+              onRollback={() => {}}
+            />
+            <SkillCard
+              skill={{
+                id: "anthropic/code-review",
+                name: "Code Review",
+                description: "Automated code review with style, security, and correctness checks.",
+                sourceId: "anthropic",
+                category: "engineering",
+                activeVersionId: null,
+                removedAt: null,
+                averageRating: 4.7,
+                ratingCount: 42,
+              }}
+              onInstall={() => {}}
+              isLoading
+            />
+          </div>
+        </SubSection>
+      </Section>
+
       {/* ============================================================ */}
       {/*  SEPARATOR                                                    */}
       {/* ============================================================ */}

ui/src/pages/SkillBrowser.tsx

@@ -0,0 +1,3 @@
+export function SkillBrowser() {
+  return <div>SkillBrowser placeholder</div>;
+}

ui/src/pages/SkillDetail.tsx

@@ -0,0 +1,3 @@
+export function SkillDetail() {
+  return <div>SkillDetail placeholder</div>;
+}