fix(skills): improve skills middleware input validation and add annotations (#211)

* fix(skills): improve skills middleware input validation and add annotations

* cr

* cr

* cr

Author: hntrl

.changeset/skills-middleware-robustness.md

@@ -0,0 +1,11 @@
+---
+"deepagents": patch
+---
+
+fix(skills): improve skills middleware input validation and add annotations
+
+Port of Python PR #1189. Hardens `parseSkillMetadataFromContent` with stricter
+coercion/trimming for all YAML fields, adds Unicode lowercase support in
+`validateSkillName`, validates and truncates compatibility length, handles
+`allowed-tools` as YAML list or space-delimited string, and shows
+license/compatibility annotations in the system prompt skill listing.

.codespellignore

@@ -1,2 +1,4 @@
 datas
-afterAll
+afterAll
+Nd
+Ll