core: improve error reporting with structured error strings and better categorization + output formatting (#11907)

* fix(telemetry): improve error reporting with structured error strings and better categorization

- Add build_error_string() that creates structured format:
  'exit_code=N | description\n---\n<last 20 log lines>'
- Fix categorize_error() to map ALL known exit codes:
  - Added: shell(1,2), proxmox(200-231), service(150-154),
    database(170-193), runtime(243-249), signal(139,141,143)
  - Split timeout from network (28 was in both)
  - Added DPKG(255) to dependency category
- Update all API functions to use build_error_string():
  post_update_to_api, post_update_to_api_extended,
  post_tool_to_api, post_addon_to_api
- Add ensure_log_on_host() calls to on_exit, on_interrupt,
  on_terminate handlers to prevent race condition where
  telemetry reports before container log is pulled to host

* fix(ui): improve error output formatting and remove redundant log paths

- error_handler: Use msg_info/msg_ok/msg_warn for container cleanup
  instead of raw echo with manual ANSI codes
- error_handler: Add ❓ icon before 'Remove broken container?' prompt
- error_handler: Indent log output with TAB for visual consistency
- build.func: Use msg_custom for installation log path display
- build.func: Use msg_info → msg_ok for container removal flow
- build.func: Use msg_warn for 'kept for debugging' message
- core.func/vm-core.func: Remove redundant container-internal log
  path display (📋 View full log) since combined log on host is
  the canonical location shown after failure

misc/vm-core.func

@@ -207,15 +207,9 @@ silent() {
     msg_custom "→" "${YWB}" "${cmd}"
 
     if [[ -s "$logfile" ]]; then
-      local log_lines=$(wc -l <"$logfile")
-      echo "--- Last 10 lines of log ---"
+      echo -e "\n${TAB}--- Last 10 lines of log ---"
       tail -n 10 "$logfile"
-      echo "----------------------------"
-
-      # Show how to view full log if there are more lines
-      if [[ $log_lines -gt 10 ]]; then
-        msg_custom "📋" "${YW}" "View full log (${log_lines} lines): ${logfile}"
-      fi
+      echo -e "${TAB}----------------------------\n"
     fi
 
     exit "$rc"