🐛 Never overwrite existing config when seeding /config 🐛

Without the .initialized marker, startup copied the baked template
over existing files in /config, resetting app.ini and regenerating
secrets. Seeding now only adds files that are missing.

- rootfs/usr/local/etc/docker/init.d/08-gitea.sh: seed copy uses cp -Rn instead of cp -Rf
- rootfs/usr/local/etc/docker/init.d/05-dockerd.sh: same change, protects a user-edited daemon.json
- rootfs/usr/local/etc/docker/init.d/zz-act_runner.sh: same change, protects user-edited runner config
- TODO.AI.md: record the bug, the verification, and the upstream template follow-up

Claude-Session: https://claude.ai/code/session_01Kae22tmhzhmfHyqc34PZbx

rootfs/usr/local/etc/docker/init.d/05-dockerd.sh

@@ -279,7 +279,7 @@ __run_precopy() {
 	if [ -d "$ETC_DIR" ] && ! [ -L "$ETC_DIR" ]; then
 		if [ ! -f "$CONF_DIR/.initialized" ]; then
 			mkdir -p "$CONF_DIR"
-			cp -Rf "$ETC_DIR/." "$CONF_DIR/" 2>/dev/null || true
+			cp -Rn "$ETC_DIR/." "$CONF_DIR/" 2>/dev/null || true
 		fi
 		rm -Rf "$ETC_DIR"
 		ln -sf "$CONF_DIR" "$ETC_DIR"