fix: add --all to cargo fmt in script/test and autoformat codebase

cargo fmt without --all fails with "Failed to find targets" in
workspace repos. This was blocking every story's gates. Also ran
cargo fmt --all to fix all existing formatting issues.

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

server/src/chat/transport/slack/verify.rs

@@ -215,7 +215,12 @@ mod tests {
         let body = b"test body";
 
         let sig = compute_test_signature("correct-secret", timestamp, body);
-        assert!(!verify_slack_signature("wrong-secret", timestamp, body, &sig));
+        assert!(!verify_slack_signature(
+            "wrong-secret",
+            timestamp,
+            body,
+            &sig
+        ));
     }
 
     /// Helper to compute a test signature using our sha256 + HMAC implementation.