chore: add firstlook workflow for PR author reputation check

Runs on every PR open/reopen/synchronize against getagentseal/firstlook
and fails the check when the author's score is 'unknown' (new or
untracked accounts). Skips bot accounts so dependabot and renovate pass
through.

This screens the same drive-by pattern that landed in PR #118 (octo-patch,
fresh automation account) without requiring a manual tier check on every
submission.

.github/workflows/firstlook.yml

@@ -0,0 +1,16 @@
+name: firstlook
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+
+jobs:
+  assess:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+      contents: read
+    steps:
+      - uses: getagentseal/firstlook@main
+        with:
+          skip-users: 'dependabot[bot],renovate[bot]'
+          fail-on: 'unknown'