Turnkey: modernize turnkey.sh with shared libraries (#13242)

* refactor(turnkey): modernize turnkey.sh with shared libraries and telemetry

- Source core.func, error_handler.func, api.func instead of custom error/msg functions
- Replace custom error_exit/warn/info/msg with msg_info/msg_ok/msg_error/msg_warn
- Upgrade validate_container_id to cluster-aware (pvesh + all-node config check)
- Add diagnostics_check() and telemetry (post_to_api / post_update_to_api)
- Add pve_check, shell_check, root_check for environment validation
- Use proper EXIT trap for cleanup (destroy container on error, restart monitor)
- Improve quoting throughout (PCT_OPTIONS as array, quoted variables)
- Secure credentials file with chmod 600
- Use exit_script for user cancellations (consistent with other scripts)

* fix(turnkey): replace diagnostics_check with inline config read

diagnostics_check() is defined in build.func which is not sourced.
Read the diagnostics config file directly instead — respects existing
user preference without prompting (turnkey has no settings menu).

* bump hardcoded names to dynamic list

* Preserve telemetry type and report failures

Respect a pre-set TELEMETRY_TYPE in misc/api.func and use it in the API payload instead of the hardcoded "lxc". In turnkey/turnkey.sh, set TELEMETRY_TYPE="turnkey" for turnkey installs and enhance turnkey_cleanup() to report failed installs to telemetry (calls post_update_to_api "failed" with the exit code when POST_TO_API_DONE is true and POST_UPDATE_DONE is not), then destroy the failed container. These changes ensure correct telemetry type propagation and that failed turnkey deployments are reported.

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Co-authored-by: Slaviša Arežina <58952836+tremor021@users.noreply.github.com>

misc/api.func

@@ -664,7 +664,7 @@ post_to_api() {
 {
     "random_id": "${RANDOM_UUID}",
     "execution_id": "${EXECUTION_ID:-${RANDOM_UUID}}",
-    "type": "lxc",
+    "type": "${TELEMETRY_TYPE}",
     "nsapp": "${NSAPP:-unknown}",
     "status": "installing",
     "ct_type": ${CT_TYPE:-1},