Add PR template and issue templates

[jasoneplumb]

Parent Epic

#104

Problem

No PR template or issue templates exist. PRs and issues are unstructured free-text. This makes the project look like it has no defined process.

Current State

{
  "issueTemplates": [],
  "pullRequestTemplates": []
}

Desired State

PR Template (.github/pull_request_template.md)

## Summary
<!-- 1-3 bullet points describing what changed and why -->

## Changes
<!-- List of specific changes -->

## Test Plan
- [ ] `npm run type-check` passes
- [ ] `npm run lint` passes
- [ ] `npm run build` succeeds
- [ ] Manual browser testing (describe what you tested)

## Screenshots
<!-- If UI changed, include before/after screenshots -->

Bug Report Template (.github/ISSUE_TEMPLATE/bug_report.md)

---
name: Bug Report
about: Report a bug or unexpected behavior
labels: bug
---

### Describe the bug
<!-- Clear, concise description of the problem -->

### Steps to reproduce
1. 
2. 
3. 

### Expected behavior
<!-- What should happen -->

### Actual behavior
<!-- What actually happens -->

### Environment
- Device: 
- OS: 
- Browser: 
- App version: 

### Screenshots
<!-- If applicable -->

Feature Request Template (.github/ISSUE_TEMPLATE/feature_request.md)

---
name: Feature Request
about: Suggest a new feature or improvement
labels: enhancement
---

### Problem
<!-- What problem does this solve? -->

### Proposed Solution
<!-- How should it work? -->

### Alternatives Considered
<!-- What other approaches did you think about? -->

### Additional Context
<!-- Screenshots, mockups, links -->

Suggested Prompt

Create GitHub issue templates and a PR template for jasoneplumb/webmap.dev:

1. Create .github/pull_request_template.md with sections for:
   Summary, Changes, Test Plan (with checkboxes for type-check, lint, 
   build, manual testing), and Screenshots.

2. Create .github/ISSUE_TEMPLATE/bug_report.md with YAML frontmatter 
   (name, about, labels: bug) and sections for: Describe the bug, 
   Steps to reproduce, Expected/Actual behavior, Environment, Screenshots.

3. Create .github/ISSUE_TEMPLATE/feature_request.md with YAML frontmatter
   (name, about, labels: enhancement) and sections for: Problem, 
   Proposed Solution, Alternatives Considered, Additional Context.

Keep templates concise — just enough structure to be useful, not so 
much that they feel bureaucratic. Commit and push.

Acceptance Criteria

• PR template appears when creating new PRs
• Issue template picker appears when creating new issues
• Bug report template includes environment fields
• Feature request template includes alternatives section