chore(gitignore): ignore sqlite WAL files and per-subsystem runtime logs

decnet.collector.log / decnet.system.log and the *.db-shm / *.db-wal
sidecars produced by the sqlite WAL journal were slipping through the
existing rules. Extend the patterns so runtime state doesn't show up
in git status.

.gitignore

@@ -17,6 +17,9 @@ linterfails.log
 webmail
 windows1
 *.db
+*.db-shm
+*.db-wal
+decnet.*.log
 decnet.json
 .env*
 .env.local