meta: add bug report issue template

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,43 @@
+name: Bug report
+description: Report a reproducible bug
+title: "[Bug]: "
+labels: ["bug"]
+body:
+  - type: textarea
+    id: summary
+    attributes:
+      label: Summary
+      description: What happened? What did you expect?
+      placeholder: A clear and concise description of the bug.
+    validations:
+      required: true
+
+  - type: textarea
+    id: steps
+    attributes:
+      label: Steps to reproduce
+      description: Provide exact steps so we can reproduce.
+      placeholder: |
+        1. ...
+        2. ...
+        3. ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs / Output
+      description: Paste relevant logs (redact secrets).
+      render: shell
+    validations:
+      required: false
+
+  - type: input
+    id: environment
+    attributes:
+      label: Environment
+      description: OS, Docker version, client (geth/reth/nethermind), etc.
+      placeholder: "Ubuntu 22.04, Docker 25.x, geth"
+    validations:
+      required: false