Add parallel test item slide

Documents the new parallel item: branches, sync (all/any), wait_for,
per-branch live prefix and report row.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/sections/items.tex

@@ -33,6 +33,7 @@
       \incode{jsonrpc} & JSON-RPC test item \\
       \incode{let} & Defining variables \\
       \incode{loop} & Container for repeating things \\
+      \incode{parallel} & Container for running branches concurrently \\
       \incode{plot} & Runtime plot utility \\
       \incode{report} & Extract a report file \\
       \incode{run} & Runs a new instance of \tum{testium} \\
@@ -326,6 +327,51 @@ end
   \end{columns}
 \end{frame}
 
+\begin{frame}[fragile]{\incode{parallel} test item}
+\begin{columns}
+  \column{0.55\textwidth}
+  \begin{itemize}
+    \item \incode{branches}: list of concurrent branches; each branch has its own \incode{steps}
+    \item \incode{sync}
+    \begin{itemize}
+      \item \incode{all} (default): wait for every branch
+      \item \incode{any}: stop the others as soon as one finishes
+    \end{itemize}
+    \item \incode{wait\_for} (per branch): poll a condition before running the branch's steps
+    \item Each branch runs in its own thread:
+    \begin{itemize}
+      \item Live output prefixed \incode{[<branch>]}
+      \item One report row per branch (clean, no interleaving)
+    \end{itemize}
+  \end{itemize}
+  \column{0.45\textwidth}
+    \begin{listing}[H]
+    \begin{minted}[fontsize=\fontsize{6}{7}\selectfont]{yaml}
+- parallel:
+    name: Read sensors
+    sync: all
+    branches:
+      - name: Temperature
+        steps:
+          - py_func:
+              name: read temp
+              file: sensors.py
+              func_name: read_temp
+      - name: Pressure
+        wait_for:
+            condition: <| "$(temp_ready)" == "1" |>
+            timeout: 5
+        steps:
+          - py_func:
+              name: read pressure
+              file: sensors.py
+              func_name: read_pressure
+    \end{minted}
+    \caption{\incode{parallel} usage example}
+    \end{listing}
+  \end{columns}
+\end{frame}
+
 \begin{frame}{\incode{dialog\_x} test items}
   \begin{itemize}
     \item Dialogs pop-up a message box with a question, information or more