feat(issue-templates): add structured bug & feature issue forms (#3359)

Replace the single runtime-information form with:
- config.yml: disable blank issues, route Q&A/ideas to Discussions, link security policy
- bug-report.yml: reproducible bug form (folds in the old runtime/environment fields + affected-area picker)
- feature-request.yml: scoped proposal form

Uses only default labels (bug/enhancement) so it is self-contained.

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -0,0 +1,159 @@
+name: 🐛 Bug report
+description: Report something that isn't working so maintainers can reproduce and fix it.
+title: "[bug] "
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to file a bug. A clear, reproducible report is the
+        single biggest factor in how fast it gets fixed.
+
+        Please fill in every required field — especially **reproduction steps** and **logs**.
+
+  - type: checkboxes
+    id: preflight
+    attributes:
+      label: Before you start
+      options:
+        - label: I searched [existing issues](https://github.com/bytedance/deer-flow/issues?q=is%3Aissue) and this is not a duplicate.
+          required: true
+        - label: I can reproduce this on the latest `main`.
+          required: false
+
+  - type: input
+    id: summary
+    attributes:
+      label: Problem summary
+      description: One sentence describing the bug.
+      placeholder: e.g. make dev fails to start the gateway service
+    validations:
+      required: true
+
+  - type: dropdown
+    id: areas
+    attributes:
+      label: Affected area(s)
+      description: Which part of DeerFlow does this touch? Select all that apply.
+      multiple: true
+      options:
+        - Frontend (UI / Next.js)
+        - Backend API (gateway / endpoints / SSE)
+        - Agents / LangGraph (graph, prompts, langgraph.json)
+        - Sandbox / Docker
+        - Skills
+        - MCP
+        - Config / setup (make, config.yaml, env)
+        - Docs
+        - Not sure
+    validations:
+      required: true
+
+  - type: textarea
+    id: actual
+    attributes:
+      label: What happened?
+      description: The actual behavior. Include the key error lines verbatim.
+      placeholder: When I do X, I expected Y but I got Z.
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected behavior
+      placeholder: What did you expect to happen instead?
+    validations:
+      required: true
+
+  - type: textarea
+    id: reproduce
+    attributes:
+      label: Steps to reproduce
+      description: Exact commands and sequence. Minimal steps that reliably reproduce the problem.
+      placeholder: |
+        1. make check
+        2. make install
+        3. make dev
+        4. ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Relevant logs
+      description: Paste key lines from logs (for example `logs/gateway.log`, `logs/frontend.log`). Redact secrets.
+      render: shell
+    validations:
+      required: true
+
+  - type: dropdown
+    id: run_mode
+    attributes:
+      label: How are you running DeerFlow?
+      options:
+        - Local (make dev)
+        - Docker (make docker-start)
+        - CI
+        - Other
+    validations:
+      required: true
+
+  - type: dropdown
+    id: os
+    attributes:
+      label: Operating system
+      options:
+        - macOS
+        - Linux
+        - Windows
+        - Other
+    validations:
+      required: true
+
+  - type: input
+    id: platform_details
+    attributes:
+      label: Platform details
+      description: Architecture and shell, if relevant.
+      placeholder: e.g. arm64, zsh
+
+  - type: input
+    id: python_version
+    attributes:
+      label: Python version
+      placeholder: e.g. Python 3.12.9
+
+  - type: input
+    id: node_version
+    attributes:
+      label: Node.js version
+      placeholder: e.g. v22.11.0
+
+  - type: input
+    id: pnpm_version
+    attributes:
+      label: pnpm version
+      placeholder: e.g. 10.26.2
+
+  - type: input
+    id: uv_version
+    attributes:
+      label: uv version
+      placeholder: e.g. 0.7.20
+
+  - type: textarea
+    id: git_info
+    attributes:
+      label: Git state
+      description: Output of `git branch --show-current` and the latest commit SHA.
+      placeholder: |
+        branch: feature/my-branch
+        commit: abcdef1
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional context
+      description: Screenshots, related issues, config snippets (redacted), or anything else that helps triage.