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/build.func

@@ -4133,8 +4133,7 @@ EOF'
 
     # Show combined log location
     if [[ -n "$CTID" && -n "${SESSION_ID:-}" ]]; then
-      echo ""
-      echo -e "${GN}✔${CL} Installation log: ${BL}${combined_log}${CL}"
+      msg_custom "📋" "${YW}" "Installation log: ${combined_log}"
     fi
 
     # Dev mode: Keep container or open breakpoint shell
@@ -4157,19 +4156,21 @@ EOF'
       exit $install_exit_code
     fi
 
-    # Prompt user for cleanup with 60s timeout (plain echo - no msg_info to avoid spinner)
+    # Prompt user for cleanup with 60s timeout
     echo ""
-    echo -en "${YW}Remove broken container ${CTID}? (Y/n) [auto-remove in 60s]: ${CL}"
+    echo -en "${TAB}❓${TAB}${YW}Remove broken container ${CTID}? (Y/n) [auto-remove in 60s]: ${CL}"
 
     if read -t 60 -r response; then
       if [[ -z "$response" || "$response" =~ ^[Yy]$ ]]; then
         # Remove container
-        echo -e "\n${TAB}${HOLD}${YW}Removing container ${CTID}${CL}"
+        echo ""
+        msg_info "Removing container ${CTID}"
         pct stop "$CTID" &>/dev/null || true
         pct destroy "$CTID" &>/dev/null || true
-        echo -e "${BFR}${CM}${GN}Container ${CTID} removed${CL}"
+        msg_ok "Container ${CTID} removed"
       elif [[ "$response" =~ ^[Nn]$ ]]; then
-        echo -e "\n${TAB}${YW}Container ${CTID} kept for debugging${CL}"
+        echo ""
+        msg_warn "Container ${CTID} kept for debugging"
 
         # Dev mode: Setup MOTD/SSH for debugging access to broken container
         if [[ "${DEV_MODE_MOTD:-false}" == "true" ]]; then
@@ -4185,11 +4186,11 @@ EOF'
       fi
     else
       # Timeout - auto-remove
-      echo -e "\n${YW}No response - auto-removing container${CL}"
-      echo -e "${TAB}${HOLD}${YW}Removing container ${CTID}${CL}"
+      echo ""
+      msg_info "No response - removing container ${CTID}"
       pct stop "$CTID" &>/dev/null || true
       pct destroy "$CTID" &>/dev/null || true
-      echo -e "${BFR}${CM}${GN}Container ${CTID} removed${CL}"
+      msg_ok "Container ${CTID} removed"
     fi
 
     # Force one final status update attempt after cleanup