Reflect 2 session logs into topic memory files

Updated: gotchas-skills.md (+$VAR paths, $() subshells, relative path
resolution), decisions.md (+CLAUDE_PROJECT_ROOT, settings.yaml relative
paths), process-lessons.md (+research history before building validators).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

memory/process-lessons.md

@@ -24,6 +24,10 @@ Multiple hooks registered for the same matcher execute concurrently, not sequent
 
 Needs ssh-agent loaded before git push to Gitea. If push hangs, check that the key is added to the agent.
 
+## Research full failure history before building validators
+
+When building a tool that detects known problems (like `validate-skill`), first research all historical failures across session logs and git commits. This reveals non-obvious patterns — e.g., `$HOME` (not just `${HOME}`) being rejected by permission checkers, which wouldn't be found from docs alone. The upfront research investment pays off in comprehensive coverage.
+
 ## Batch parallel file creation for efficiency
 
 Creating many independent files in a single Write batch (e.g., 11 best-practices files at once) is significantly faster than sequential creation.