Fix integer rendering and restore bullet points in Slack DMs

- Use floatingOrInteger in numberToScalarEvent so integers render as
  '30' instead of '30.0' in generated YAML
- Restore '•' bullet character in Slack DM notifications; '-' does not
  render as a bullet in Slack mrkdwn

Co-authored-by: Adrea Snow <adreasnow@users.noreply.github.com>

Author: github-actions[bot]

.github/workflows/haskell-ci.yml

@@ -20,7 +20,7 @@ jobs:
   generate-matrix:
     name: Generate matrix from cabal
     runs-on: ubuntu-24.04
-    timeout-minutes: 30.0
+    timeout-minutes: 30
     outputs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}
     steps:
@@ -37,7 +37,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     needs:
       - generate-matrix
-    timeout-minutes: 30.0
+    timeout-minutes: 30
     container:
       image: buildpack-deps:jammy
     strategy: