Add CLAUDE.md and update Doom Emacs config

- Add CLAUDE.md for Claude Code guidance
- Update gptel config to use Claude Sonnet 4 with key from ~/.secrets/claude_key
- Update elfeed filters to exclude -wait tag
- Enable terraform module in init.el
- Update org agenda files for 2026
- Fix org-hugo link rendering for vanilla Markdown

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

init.el

@@ -104,7 +104,7 @@
        ;;prodigy           ; FIXME managing external services & code builders
        ;;rgb               ; creating color strings
        ;;taskrunner        ; taskrunner for all your projects
-       ;;terraform         ; infrastructure as code
+       terraform         ; infrastructure as code
        ;;tmux              ; an API for interacting with tmux
        tree-sitter       ; syntax and parsing, sitting in a tree...
        ;;upload            ; map local to remote projects via ssh/ftp