fix: replace generic exit 1 with specific exit codes in ct/ and install/ scripts

Part of #12467 — scripts only (no framework changes).

New exit codes 250-254 registered in api.func and error_handler.func:
- 250: App download failed or version not determined
- 251: App file extraction failed (corrupt/incomplete archive)
- 252: App required file or resource not found
- 253: App data migration required — update aborted
- 254: App user declined prompt or input timed out

Existing codes reused where applicable:
- 10: privileged/Docker required (unifi-os-server)
- 64: invalid user input (postgresql, tomcat)
- 71: system error (pulse useradd)
- 150: service failed to start (docker, npmplus)
- 153: build failed (booklore)
- 233: app not installed (evcc, endurain, grafana, loki, itsm-ng)
- 236: hardware not detected (unifi-os-server /dev/net/tun)
- 238: OS not supported (frigate)

install/alpine-postgresql-install.sh

@@ -14,7 +14,7 @@ network_check
 update_os
 
 read -r -p "${TAB3}Enter PostgreSQL version (15/16/17): " ver
-[[ $ver =~ ^(15|16|17)$ ]] || { echo "Invalid version"; exit 1; }
+[[ $ver =~ ^(15|16|17)$ ]] || { echo "Invalid version"; exit 64; }
 
 msg_info "Installing PostgreSQL ${ver}"
 $STD apk add --no-cache postgresql${ver} postgresql${ver}-contrib postgresql${ver}-openrc sudo