chore: add issue templates and a pull-request template

The repo had no .github issue or PR templates, so bug reports arrived
with inconsistent detail and questions landed on the tracker instead of
Discussions.

Add GitHub community templates:
- ISSUE_TEMPLATE/bug_report.yml: structured form (OS, pipeline, runtime,
  repro, expected vs actual, logs)
- ISSUE_TEMPLATE/feature_request.yml: problem / solution / alternatives
- ISSUE_TEMPLATE/config.yml: disables blank issues and routes questions,
  ideas, and show-and-tell to the existing Discussions categories
- PULL_REQUEST_TEMPLATE.md: summary, linked issue, testing, checklist

Additive only; no source changes.

Closes #189

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,69 @@
+name: Bug report
+description: Report a reproducible problem with OpenMontage
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to file a bug. Please fill in the fields below so it can be reproduced and triaged quickly.
+        For questions or help, use [GitHub Discussions](https://github.com/calesthio/OpenMontage/discussions) instead.
+  - type: textarea
+    id: summary
+    attributes:
+      label: Summary
+      description: A clear, one-paragraph description of the bug.
+    validations:
+      required: true
+  - type: input
+    id: os
+    attributes:
+      label: Operating system
+      placeholder: e.g. Windows 11, macOS 14.5, Ubuntu 24.04
+    validations:
+      required: true
+  - type: input
+    id: pipeline
+    attributes:
+      label: Pipeline
+      description: Which pipeline were you running, if any?
+      placeholder: e.g. cinematic, explainer, character-animation
+    validations:
+      required: false
+  - type: input
+    id: runtime
+    attributes:
+      label: Runtime / renderer
+      placeholder: e.g. remotion, hyperframes
+    validations:
+      required: false
+  - type: textarea
+    id: repro
+    attributes:
+      label: Steps to reproduce
+      description: The exact commands or actions that trigger the bug.
+      placeholder: |
+        1. Run `...`
+        2. ...
+        3. See error
+    validations:
+      required: true
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected behavior
+    validations:
+      required: true
+  - type: textarea
+    id: actual
+    attributes:
+      label: Actual behavior
+    validations:
+      required: true
+  - type: textarea
+    id: logs
+    attributes:
+      label: Relevant logs or error output
+      description: Paste any error messages or tracebacks. This is automatically formatted as code.
+      render: shell
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,11 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Questions & troubleshooting
+    url: https://github.com/calesthio/OpenMontage/discussions/categories/q-a
+    about: Ask setup, pipeline, or troubleshooting questions in Discussions.
+  - name: Ideas & feature brainstorming
+    url: https://github.com/calesthio/OpenMontage/discussions/categories/ideas
+    about: Propose and discuss new pipelines, tools, or integrations.
+  - name: Show and Tell
+    url: https://github.com/calesthio/OpenMontage/discussions/categories/show-and-tell
+    about: Share videos, prompts, or workflows you've built.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,38 @@
+name: Feature request
+description: Suggest a new tool, pipeline, integration, or improvement
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Have an idea? If it's open-ended or you want to discuss direction first, consider posting in
+        [Discussions → Ideas](https://github.com/calesthio/OpenMontage/discussions/categories/ideas).
+        Use this form for a concrete, actionable request.
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem / motivation
+      description: What problem does this solve, or what is missing today?
+    validations:
+      required: true
+  - type: textarea
+    id: solution
+    attributes:
+      label: Proposed solution
+      description: Describe the tool, pipeline, or change you'd like.
+    validations:
+      required: true
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives considered
+      description: Any other approaches you've thought about.
+    validations:
+      required: false
+  - type: textarea
+    id: context
+    attributes:
+      label: Additional context
+      description: Links, mockups, references, or examples.
+    validations:
+      required: false

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,30 @@
+<!--
+Thanks for contributing to OpenMontage! Please fill in the sections below.
+Keep PRs focused — one logical change per PR is easier to review and merge.
+-->
+
+## Summary
+
+<!-- What does this PR do, and why? -->
+
+## Related issue
+
+<!-- Link the issue this closes, e.g. "Closes #123". Use "Refs #123" if it only relates. -->
+Closes #
+
+## Changes
+
+<!-- Bullet the notable changes. -->
+-
+
+## Testing
+
+<!-- How did you verify this? Commands run, manual steps, platforms checked. -->
+-
+
+## Checklist
+
+- [ ] The change is focused on a single logical concern.
+- [ ] I ran the relevant tests locally (`make test-contracts` / `make test`) where applicable.
+- [ ] I updated docs/README if behavior or usage changed.
+- [ ] No unrelated files (build artifacts, local config) are included in the diff.