Add IDE configuration and planning documentation

- Add IntelliJ IDEA .iml module configuration file
- Add planning/ directory with enhancement documentation:
  - ENHANCEMENTS.md: 17 enhancement opportunities identified during codebase analysis
  - json-output-design.md: Design proposal for JSON output support

These files provide valuable context for future development and IDE integration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: elifarley

cedarmapper.iml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="PYTHON_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>