Fix tmpfs ownership so storkit user can write to home dir

The tmpfs at /home/storkit defaulted to root ownership (mode=755),
so Claude Code couldn't write ~/.claude.json or ~/.cache/. Set
uid=999,gid=999 to match the storkit user.

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

docker/docker-compose.yml

@@ -72,7 +72,7 @@ services:
     read_only: true
     tmpfs:
       - /tmp:size=512M
-      - /home/storkit:size=512M
+      - /home/storkit:size=512M,uid=999,gid=999
 
     # Drop all Linux capabilities, then add back only what's needed.
     # SETUID/SETGID needed by Claude Code's PTY allocation (openpty).