feat(FN-1212): update header with circular Fusion logo

- Replace the header SVG mark with a circular outline and filled path-based glyph using currentColor
- Keep logo semantics and ordering intact while modernizing the visual treatment
- Update Header tests to assert currentColor-based geometry and verify the stroked outer circle

packages/dashboard/app/components/Header.tsx

@@ -272,10 +272,17 @@ export function Header({
             aria-label="Fusion logo"
             role="img"
           >
-            <circle cx="44" cy="44" r="20" fill="currentColor" />
-            <circle cx="84" cy="44" r="20" fill="currentColor" />
-            <circle cx="44" cy="84" r="20" fill="currentColor" />
-            <circle cx="84" cy="84" r="20" fill="currentColor" />
+            <circle
+              cx="64"
+              cy="64"
+              r="52"
+              stroke="currentColor"
+              strokeWidth="8"
+            />
+            <path
+              d="M26 101C44 82 62 64 82 45C90 37 98 30 104 24C96 35 89 47 81 60C70 79 57 95 43 108C38 112 32 108 26 101Z"
+              fill="currentColor"
+            />
           </svg>
           <h1 className="logo">Fusion</h1>
         </div>

packages/dashboard/app/components/__tests__/Header.test.tsx

@@ -49,9 +49,16 @@ describe("Header", () => {
     const logo = screen.getByLabelText("Fusion logo");
     expect(logo).toBeDefined();
     expect(logo.tagName.toLowerCase()).toBe("svg");
-    // The SVG should have the currentColor" fill
-    const circles = logo.querySelectorAll("circle");
-    expect(circles).toHaveLength(4);
+
+    // The SVG should expose currentColor-driven geometry for theme-aware coloring
+    const currentColorShapes = logo.querySelectorAll(
+      '[fill="currentColor"], [stroke="currentColor"]'
+    );
+    expect(currentColorShapes.length).toBeGreaterThan(0);
+
+    // The new logo keeps a single outer circle boundary
+    const outerCircle = logo.querySelector("circle[stroke='currentColor']");
+    expect(outerCircle).not.toBeNull();
   });
 
   it("renders the logo before the h1 element", () => {