Document preferred build command in CLAUDE.md

Update build workflow to include 'make formats' as part of standard build:
- make clean && make html && make formats

This ensures all agent-friendly formats are generated:
- Markdown versions (index.md via pandoc)
- Plain text (index.txt)
- JSON Feed (feeds/all.json)
- JSON Blog (blog.json with Markdown content)
- AI agent onboarding (llms.txt)

Makes the preferred build workflow explicit for future reference.

CLAUDE.md

@@ -37,7 +37,7 @@ you are acting on behalf of russell ballestrini. don't fuck up.
 ## CRITICAL PELICAN TESTING WORKFLOW
 
 ### BEFORE ANY COMMIT:
-1. **ALWAYS test Pelican build**: `make clean && make html`
+1. **ALWAYS test Pelican build**: `make clean && make html && make formats`
 2. **Check for build errors**: Pelican will fail on RST syntax errors, missing files, etc.
 3. **Verify output**: `make serve` and check localhost:8000
 4. **NEVER commit without testing the build**
@@ -49,13 +49,29 @@ you are acting on behalf of russell ballestrini. don't fuck up.
 - Missing images/files break the build
 - Invalid slugs/filenames cause issues
 
+### PREFERRED BUILD COMMAND:
+```bash
+make clean && make html && make formats
+```
+
+This generates:
+- HTML output from RST/MD sources
+- Markdown versions (index.md) via pandoc
+- Plain text versions (index.txt)
+- JSON Feed (feeds/all.json)
+- JSON Blog (blog.json) with Markdown content
+- AI agent onboarding (llms.txt)
+
 ### PROPER DEVELOPMENT WORKFLOW:
 ```bash
 # Setup virtual environment (once)
 make venv
 
-# Test changes before commit
-make clean && make html && make serve
+# Test changes before commit (PREFERRED BUILD)
+make clean && make html && make formats
+
+# Optional: serve locally to verify
+make serve
 
 # Check localhost:8000 for issues
 # Only commit if build succeeds