docs: add Communication patterns section to all plugin CLAUDE.md

Standardize named-markdown-link guidance across all plugins so file://
references render as independently clickable links in terminals like
Ghostty (bare file:// URLs only make the first clickable).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/human-friendly-style/CLAUDE.md

@@ -45,3 +45,20 @@ If `keep-coding-instructions` is removed or set to `false`, Claude Code will str
 - Per-plugin variants (code-focused, deep-technical, etc.) — would belong in a future v1.1 if there's real demand
 - Forcing the style on other plugins — it remains opt-in. Other plugins may reference it in their READMEs.
 - Translation of the style file itself into Norwegian — defeats the purpose of language-agnostic instruction
+
+## Communication patterns
+
+### Linking to local files
+
+When pointing to local files in responses, always use markdown link syntax with a descriptive name:
+
+- Use `[Human-friendly name](file:///absolute/path)` — never bare `file:///...` URLs or autolinks `<file://...>`.
+- Always use absolute paths. Never `~/` or relative paths.
+- For multiple files, render as a bullet list of named markdown links.
+
+Why: bare `file://` URLs only render the first as clickable across multiple lines. Named markdown links make each entry independently clickable and look cleaner.
+
+Example:
+
+- [Brief](file:///Users/ktg/.../brief.html)
+- [Research summary](file:///Users/ktg/.../research/summary.md)