feat(06-01): migrate categories from emoji to Lucide icon field

- Rename emoji column to icon in schema, Zod schemas, and all services
- Add Drizzle migration with emoji-to-icon data conversion
- Update test helper, seed, and all test files for icon field
- All 87 tests pass with new icon-based schema

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/routes/categories.test.ts

@@ -31,13 +31,13 @@ describe("Category Routes", () => {
     const res = await app.request("/api/categories", {
       method: "POST",
       headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ name: "Shelter", emoji: "\u{26FA}" }),
+      body: JSON.stringify({ name: "Shelter", icon: "tent" }),
     });
 
     expect(res.status).toBe(201);
     const body = await res.json();
     expect(body.name).toBe("Shelter");
-    expect(body.emoji).toBe("\u{26FA}");
+    expect(body.icon).toBe("tent");
     expect(body.id).toBeGreaterThan(0);
   });
 
@@ -55,7 +55,7 @@ describe("Category Routes", () => {
     const catRes = await app.request("/api/categories", {
       method: "POST",
       headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ name: "Shelter", emoji: "\u{26FA}" }),
+      body: JSON.stringify({ name: "Shelter", icon: "tent" }),
     });
     const cat = await catRes.json();