refactor(auth): migrate use-case binders to wireUseCase

Replace inline withSpan + withCapture blocks for signIn, signUp, and
signOut use cases in both bind-production.ts and bind-dev-seed.ts with
wireUseCase calls. Removes 27 lines of boilerplate per binder file.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

coverage/summary.json

@@ -1,14 +1,14 @@
 {
-  "generatedAt": "2026-05-13T14:38:41.601Z",
-  "commit": "6428f10",
+  "generatedAt": "2026-05-13T17:51:01.137Z",
+  "commit": "e08e0a1",
   "repo": {
-    "statements": 95.87,
+    "statements": 95.86,
     "branches": 88.91,
     "functions": 100,
-    "lines": 95.87,
+    "lines": 95.86,
     "counts": {
-      "lf": 3123,
-      "lh": 2994,
+      "lf": 3117,
+      "lh": 2988,
       "brf": 487,
       "brh": 433,
       "fnf": 142,
@@ -17,13 +17,13 @@
   },
   "byPackage": {
     "@repo/auth": {
-      "statements": 93.85,
+      "statements": 93.81,
       "branches": 90.82,
       "functions": 100,
-      "lines": 93.85,
+      "lines": 93.81,
       "counts": {
-        "lf": 797,
-        "lh": 748,
+        "lf": 791,
+        "lh": 742,
         "brf": 98,
         "brh": 89,
         "fnf": 44,