revert: keep UI test signing unchanged

AGENTS.md

@@ -365,8 +365,9 @@ Environment and accessibility issues encountered while running `BrewUITests` on
    `CODE_SIGN_IDENTITY=-` fixes it: the runner is ad-hoc signed as `sh.brew.BrewUITests.xctrunner`
    with a valid seal, and ad-hoc needs no identity, team or profile, so it works on CI too.
 
-   `scripts/test-ui` and the `ui-test` CI job use the same ad-hoc signing path as `scripts/test-e2e`.
-   Do not reintroduce `CODE_SIGNING_ALLOWED=NO` for either test plan.
+   **Watch for:** `scripts/test-ui` and the `ui-test` CI job still pass `CODE_SIGNING_ALLOWED=NO`.
+   That is the same latent defect – if the deterministic suite ever starts failing this way, drop
+   the flag there as well rather than hunting the hang.
 
 ### Debugging gotcha specific to this environment
 

scripts/test-ui

@@ -27,7 +27,6 @@ rm -rf UITestResults.xcresult
 # connection" on a real Mac, even though the identical run against the default
 # ~/Library/Developer/Xcode/DerivedData location passes in seconds. Root cause not chased down
 # further than that — use the default location rather than the one that's confirmed broken.
-# Keep ad-hoc signing enabled: the copied XCTRunner must be re-signed after the test bundle is added.
 xcodebuild test \
   -project Homebrew.xcodeproj \
   -scheme Brew-UI \
@@ -38,6 +37,7 @@ xcodebuild test \
   CODE_SIGN_STYLE=Manual \
   CODE_SIGN_IDENTITY=- \
   CODE_SIGNING_REQUIRED=NO \
+  CODE_SIGNING_ALLOWED=NO \
   "$@"
 
 echo "==> UI tests passed."