Community health: YAML bug template, welcome bot (#3)

- Add YAML form bug report template with Python-specific fields
- Add welcome bot workflow for first-time contributors

Co-authored-by: zeevdr <zeev.dreifuss@ownera.io>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,68 @@
+name: Bug Report
+description: Report a bug in the OpenDecree Python SDK
+labels: [bug]
+body:
+  - type: textarea
+    id: description
+    attributes:
+      label: Describe the bug
+      description: A clear description of what the bug is.
+    validations:
+      required: true
+  - type: textarea
+    id: reproduce
+    attributes:
+      label: To reproduce
+      description: Steps to reproduce the behavior.
+      placeholder: |
+        1. ...
+        2. ...
+    validations:
+      required: true
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected behavior
+      description: What you expected to happen.
+    validations:
+      required: true
+  - type: dropdown
+    id: component
+    attributes:
+      label: Component
+      options:
+        - Sync client (DecreeClient)
+        - Async client (AsyncDecreeClient)
+        - ConfigWatcher
+        - Other
+    validations:
+      required: true
+  - type: input
+    id: version
+    attributes:
+      label: SDK version
+      placeholder: e.g., 0.1.0
+    validations:
+      required: true
+  - type: input
+    id: python-version
+    attributes:
+      label: Python version
+      placeholder: e.g., 3.12
+    validations:
+      required: true
+  - type: input
+    id: server-version
+    attributes:
+      label: OpenDecree server version
+      placeholder: e.g., v0.5.0
+  - type: input
+    id: os
+    attributes:
+      label: OS
+      placeholder: e.g., Linux, macOS, Windows
+  - type: textarea
+    id: context
+    attributes:
+      label: Additional context
+      description: Logs, screenshots, or anything else that helps.

.github/workflows/welcome.yml

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+name: Welcome
+
+on:
+  issues:
+    types: [opened]
+  pull_request_target:
+    types: [opened]
+
+permissions:
+  issues: write
+  pull-requests: write
+
+jobs:
+  welcome:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/first-interaction@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          issue-message: |
+            Thanks for opening your first issue! We'll take a look soon.
+
+            In the meantime, search [Discussions](https://github.com/opendecree/decree/discussions) for related topics.
+          pr-message: |
+            Thanks for your first pull request! We appreciate the contribution.
+
+            Before review, please make sure tests pass: `cd sdk && pytest`