ci(fuzz): Add workflow_dispatch and minimize step (#325)

.github/workflows/fuzz.yml

@@ -5,6 +5,7 @@ on:
       - v*.x
   schedule:
     - cron: '11 15 * * *' # every day at 15:11 UTC
+  workflow_dispatch: {}
 name: Fuzz
 env:
   FUZZ_CORPUS_URL: 'https://jxl-oxide-fixtures.tirr.dev/fuzz-corpus.tar.zst'
@@ -61,8 +62,15 @@ jobs:
             -max_len=4096 \
             -timeout=5 \
             -max_total_time=1200
+      - name: Minimize corpus
+        id: minimize
+        run: |
+          cargo fuzz cmin libfuzzer-decode -- \
+            -max_len=8192 \
+            -timeout=5 \
+            -max_total_time=600
       - uses: actions/upload-artifact@v4
-        if: ${{ !cancelled() && steps.fuzz.outcome == 'failure' }}
+        if: ${{ !cancelled() && (steps.fuzz.outcome == 'failure' || steps.minimize.outcome == 'failure') }}
         with:
           name: fuzz-artifacts
           path: fuzz/artifacts/