Add PR template, issue templates, and contribution policy (#126)

* chore: add PR template, issue templates, and contribution policy

Drive-by feature PRs are becoming a problem. This adds guardrails:

- PR template with type selection, checklist, and AI disclosure
- Bug report issue template (structured YAML form)
- Issue config that redirects features to Discussions and disables blank issues
- PR compliance workflow that enforces template completion and requires
  a Discussion link for feature PRs
- Contribution policy in CONTRIBUTING.md (acceptance tiers, AI PR rules)
- Agent-facing rules in AGENTS.md (follow the template, no bulk changes)

* fornat

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,51 @@
+name: Bug Report
+description: Report a bug in EmDash
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for reporting a bug. Please fill out the sections below so we can reproduce and fix it.
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Description
+      description: What happened? What did you expect to happen?
+    validations:
+      required: true
+
+  - type: textarea
+    id: reproduction
+    attributes:
+      label: Steps to reproduce
+      description: Minimal steps to trigger the bug. Include code snippets, config, or a link to a reproduction repo if possible.
+      placeholder: |
+        1. Create a collection with ...
+        2. Navigate to ...
+        3. Click ...
+        4. See error
+    validations:
+      required: true
+
+  - type: textarea
+    id: environment
+    attributes:
+      label: Environment
+      description: Relevant version info.
+      placeholder: |
+        - emdash version: x.x.x
+        - Node.js version: x.x.x
+        - Runtime: Node / Cloudflare Workers
+        - OS: macOS / Linux / Windows
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs / error output
+      description: Paste any relevant error messages or stack traces.
+      render: shell
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Feature request
+    url: https://github.com/emdash-cms/emdash/discussions/categories/ideas
+    about: Propose a feature in Discussions. Feature PRs without a prior approved Discussion will be closed.
+  - name: Question
+    url: https://github.com/emdash-cms/emdash/discussions/categories/q-a
+    about: Ask a question in Discussions.