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/error_handler.func

@@ -175,9 +175,9 @@ error_handler() {
   fi
 
   if [[ -n "$active_log" && -s "$active_log" ]]; then
-    echo "--- Last 20 lines of silent log ---"
+    echo -e "\n${TAB}--- Last 20 lines of log ---"
     tail -n 20 "$active_log"
-    echo "-----------------------------------"
+    echo -e "${TAB}-----------------------------------\n"
 
     # Detect context: Container (INSTALL_LOG set + /root exists) vs Host (BUILD_LOG)
     if [[ -n "${INSTALL_LOG:-}" && -d /root ]]; then
@@ -204,23 +204,50 @@ error_handler() {
         fi
 
         echo ""
-        echo -en "${YW}Remove broken container ${CTID}? (Y/n) [auto-remove in 60s]: ${CL}"
+        if declare -f msg_custom >/dev/null 2>&1; then
+          echo -en "${TAB}❓${TAB}${YW}Remove broken container ${CTID}? (Y/n) [auto-remove in 60s]: ${CL}"
+        else
+          echo -en "${YW}Remove broken container ${CTID}? (Y/n) [auto-remove in 60s]: ${CL}"
+        fi
 
         if read -t 60 -r response; then
           if [[ -z "$response" || "$response" =~ ^[Yy]$ ]]; then
-            echo -e "\n${YW}Removing container ${CTID}${CL}"
+            echo ""
+            if declare -f msg_info >/dev/null 2>&1; then
+              msg_info "Removing container ${CTID}"
+            else
+              echo -e "${YW}Removing container ${CTID}${CL}"
+            fi
             pct stop "$CTID" &>/dev/null || true
             pct destroy "$CTID" &>/dev/null || true
-            echo -e "${GN}✔${CL} Container ${CTID} removed"
+            if declare -f msg_ok >/dev/null 2>&1; then
+              msg_ok "Container ${CTID} removed"
+            else
+              echo -e "${GN}✔${CL} Container ${CTID} removed"
+            fi
           elif [[ "$response" =~ ^[Nn]$ ]]; then
-            echo -e "\n${YW}Container ${CTID} kept for debugging${CL}"
+            echo ""
+            if declare -f msg_warn >/dev/null 2>&1; then
+              msg_warn "Container ${CTID} kept for debugging"
+            else
+              echo -e "${YW}Container ${CTID} kept for debugging${CL}"
+            fi
           fi
         else
           # Timeout - auto-remove
-          echo -e "\n${YW}No response - auto-removing container${CL}"
+          echo ""
+          if declare -f msg_info >/dev/null 2>&1; then
+            msg_info "No response - removing container ${CTID}"
+          else
+            echo -e "${YW}No response - removing container ${CTID}${CL}"
+          fi
           pct stop "$CTID" &>/dev/null || true
           pct destroy "$CTID" &>/dev/null || true
-          echo -e "${GN}✔${CL} Container ${CTID} removed"
+          if declare -f msg_ok >/dev/null 2>&1; then
+            msg_ok "Container ${CTID} removed"
+          else
+            echo -e "${GN}✔${CL} Container ${CTID} removed"
+          fi
         fi
 
         # Force one final status update attempt after cleanup
@@ -254,6 +281,10 @@ on_exit() {
   # post_to_api was called ("installing" sent) but post_update_to_api was never called
   if [[ "${POST_TO_API_DONE:-}" == "true" && "${POST_UPDATE_DONE:-}" != "true" ]]; then
     if declare -f post_update_to_api >/dev/null 2>&1; then
+      # Ensure log is accessible on host before reporting
+      if declare -f ensure_log_on_host >/dev/null 2>&1; then
+        ensure_log_on_host
+      fi
       if [[ $exit_code -ne 0 ]]; then
         post_update_to_api "failed" "$exit_code"
       else
@@ -273,6 +304,10 @@ on_exit() {
 # - Exits with code 130 (128 + SIGINT=2)
 # ------------------------------------------------------------------------------
 on_interrupt() {
+  # Ensure log is accessible on host before reporting
+  if declare -f ensure_log_on_host >/dev/null 2>&1; then
+    ensure_log_on_host
+  fi
   # Report interruption to telemetry API (prevents stuck "installing" records)
   if declare -f post_update_to_api >/dev/null 2>&1; then
     post_update_to_api "failed" "130"
@@ -294,6 +329,10 @@ on_interrupt() {
 # - Triggered by external process termination
 # ------------------------------------------------------------------------------
 on_terminate() {
+  # Ensure log is accessible on host before reporting
+  if declare -f ensure_log_on_host >/dev/null 2>&1; then
+    ensure_log_on_host
+  fi
   # Report termination to telemetry API (prevents stuck "installing" records)
   if declare -f post_update_to_api >/dev/null 2>&1; then
     post_update_to_api "failed" "143"