Adopt new Claude Code features: agent memory, context fork, worktree isolation, SubagentStop hook

- Add `memory: project` to 14 specialist agents for cross-session learning
- Add `context: fork` + `agent:` to 6 analysis skills to preserve main context
- Add `isolation: worktree` to prototyper agent for safe throwaway experiments
- Add SubagentStop hook to complete agent audit trail (start + stop logging)

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

.claude/skills/reverse-document/SKILL.md

@@ -4,6 +4,8 @@ description: "Generate design or architecture documents from existing implementa
 argument-hint: "<type> <path> (e.g., 'design src/gameplay/combat' or 'architecture src/core')"
 user-invocable: true
 allowed-tools: Read, Glob, Grep, Write, Edit, Bash
+context: fork
+agent: Explore
 ---
 
 # Reverse Documentation