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>

CLAUDE.md

@@ -75,3 +75,20 @@ Cycle archival: `/okr:oppsett arkiver` — moves `syklus/` to `historikk/`, gene
 /okr:oppsett arkiver ──→ cycle archival + retrospektiv-generering
 SessionStart ──→ coaching-hook.mjs (proactive coaching)
 ```
+
+## 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)