docs: add CLAUDE.md with submodule sync instructions

Ensures Claude Code knows to update the indiekit-cloudron submodule
after making changes to this theme repo.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,158 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code when working with the Indiekit Eleventy theme.
+
+## Project Overview
+
+This is an Eleventy theme designed for use with Indiekit, supporting IndieWeb post types (notes, articles, bookmarks, likes, replies, reposts, photos). It's used as a **Git submodule** in the `indiekit-cloudron` deployment repository.
+
+**Live Site:** https://rmendes.net
+**Parent Repo:** `/home/rick/code/indiekit-cloudron` (Cloudron deployment)
+
+## Submodule Relationship
+
+```
+indiekit-cloudron/                    # Cloudron deployment repo
+└── eleventy-site/                    # THIS REPO as submodule
+    ├── _includes/
+    ├── _data/
+    ├── content -> /app/data/content  # Symlink at runtime
+    └── ...
+```
+
+## CRITICAL: Submodule Sync Workflow
+
+**After ANY changes to this repo, you MUST also update the parent repo's submodule reference.**
+
+### Step-by-Step Process
+
+1. **Make changes in this repo** (indiekit-eleventy-theme)
+2. **Commit and push** this repo
+3. **Update the submodule** in indiekit-cloudron:
+
+```bash
+# After pushing changes to this theme repo:
+cd /home/rick/code/indiekit-cloudron
+git submodule update --remote eleventy-site
+git add eleventy-site
+git commit -m "chore: update eleventy-site submodule"
+git push origin main
+```
+
+4. **Redeploy Cloudron** to apply changes:
+
+```bash
+cloudron build --no-cache
+cloudron update --app rmendes.net
+```
+
+### Automated Reminder
+
+If you forget to update the submodule, the changes will NOT appear on the live site. Always complete both steps.
+
+## Commands
+
+```bash
+# Install dependencies (for local development)
+npm install
+
+# Build site locally
+npm run build
+
+# Development server with hot reload
+npm run dev
+```
+
+## Architecture
+
+### Post Types & Collections
+
+| Collection | Path | Description |
+|------------|------|-------------|
+| posts | `content/**/*.md` | All content combined |
+| notes | `content/notes/**/*.md` | Short posts |
+| articles | `content/articles/**/*.md` | Long-form articles |
+| bookmarks | `content/bookmarks/**/*.md` | Saved links |
+| photos | `content/photos/**/*.md` | Photo posts |
+| likes | `content/likes/**/*.md` | Liked content |
+| replies | `content/replies/**/*.md` | Reply posts |
+| reposts | `content/reposts/**/*.md` | Reposted content |
+
+### IndieWeb Property Names
+
+**IMPORTANT:** The Indiekit Eleventy preset uses `camelcaseKeys` to convert Microformat properties:
+
+| Microformat | Indiekit Frontmatter | Template Variable |
+|-------------|---------------------|-------------------|
+| `bookmark-of` | `bookmarkOf` | `bookmarkOf` or `bookmark_of` |
+| `like-of` | `likeOf` | `likeOf` or `like_of` |
+| `in-reply-to` | `inReplyTo` | `inReplyTo` or `in_reply_to` |
+| `repost-of` | `repostOf` | `repostOf` or `repost_of` |
+
+All templates support BOTH camelCase (from Indiekit) and underscore names (legacy) for backwards compatibility:
+
+```nunjucks
+{% set bookmarkedUrl = bookmarkOf or bookmark_of %}
+{% if bookmarkedUrl %}
+  <a href="{{ bookmarkedUrl }}">{{ bookmarkedUrl }}</a>
+{% endif %}
+```
+
+### Key Templates
+
+| File | Purpose |
+|------|---------|
+| `_includes/layouts/post.njk` | Individual post layout, Bridgy syndication |
+| `_includes/components/reply-context.njk` | Displays bookmark/like/reply/repost context |
+| `bookmarks.njk` | Bookmarks collection page |
+| `likes.njk` | Likes collection page |
+| `replies.njk` | Replies collection page |
+| `reposts.njk` | Reposts collection page |
+
+### Bridgy Syndication
+
+The `post.njk` layout includes syndication content for Bridgy (Bluesky/Mastodon):
+
+```nunjucks
+{# Interaction posts include target URL in syndication #}
+<p class="p-summary e-bridgy-mastodon-content e-bridgy-bluesky-content hidden">
+  🔖 {{ bookmarkedUrl }} - {{ description }}
+</p>
+```
+
+## Code Style
+
+- ESM modules (`"type": "module"` in package.json)
+- Nunjucks templates (`.njk`)
+- Tailwind CSS for styling
+- `markdownTemplateEngine: false` to prevent parsing `{{` in content
+
+## Common Tasks
+
+### Adding a New Post Type
+
+1. Create collection in `eleventy.config.js`
+2. Create collection page (e.g., `newtype.njk`)
+3. Update `reply-context.njk` if it has a target URL property
+4. Update `post.njk` Bridgy content if needed
+5. **Commit, push, and update submodule in indiekit-cloudron**
+
+### Fixing Template Issues
+
+1. Check property names match Indiekit output (camelCase)
+2. Support both camelCase and underscore for compatibility
+3. Test locally with `npm run dev`
+4. **Commit, push, and update submodule in indiekit-cloudron**
+
+## Related Repositories
+
+- **indiekit-cloudron** (`/home/rick/code/indiekit-cloudron`) - Cloudron deployment, contains this as submodule
+- **indiekit** (`/home/rick/code/indiekit`) - Indiekit core (upstream reference)
+
+## Anti-Patterns
+
+1. ❌ Forgetting to update submodule in indiekit-cloudron after changes
+2. ❌ Using only underscore property names (Indiekit uses camelCase)
+3. ❌ Using `markdownTemplateEngine: "njk"` (breaks code samples)
+4. ❌ CommonJS syntax in ESM project
+5. ❌ Hardcoding URLs instead of using site data