Add TRO flow program deriving the control objects from the layout

Sister program to material_flow.py with the same switches, but --tosvg draws the
flow diagram of the TROs instead of the individual objects. It reuses
read_elements and build_graph, so CSV parsing and direction logic exist once.

A TRO is the control logic of one hand-over point, derived from the separator and
what is attached to it, following doc/500573_Mubea/TRO_Identifikation_500573.md:

  Gefaellestrecke, >= 2 lines sharing feed/discharge -> PinStore_Auto per group
  Gefaellestrecke, single line                       -> 1Sep
  Strecke (driven)                                   -> Vario per segment
  Kreisel lane                                       -> 1Sep

A scanner at the separator deliberately does not change the type: in connect.ini
separators with a scanner are predominantly 1Sep, and 1Sep_SSCC is reserved for
the SSCC/end-measurement/WCS case, which a mechanical layout cannot reveal.
Affected points are reported as hints instead. A host with 2 or 3 outgoing flow
edges upgrades 1Sep to 1Sep1Swi/1Sep2Swi.

Connectivity contracts passive nodes: material runs separator to separator, so a
carousel lane carrying no TRO is traversed rather than treated as a dead end.
Without that, a lone separator on a spur loop would be reported as an orphan
purely as an artifact of the model. Each TRO must connect to at least one other;
otherwise an error file is written and the exit code is 3.

Each TRO also carries a plant coordinate - the centroid of the components it was
built from, so a 1Sep1Swi sits between its separator and its switch. Written into
the DOT as a pos attribute (1:100), which dot ignores and "neato -n" can use to
draw the diagram to scale.

Types, function blocks, components and colours come exclusively from
lib/tro_catalog.py.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

bin/tro_flow.bat

@@ -0,0 +1,33 @@
+@echo off
+REM ================================================================
+REM SPS_SKEL - TROs ermitteln und TRO-Flussdiagramm erzeugen
+REM ================================================================
+REM Aufruf:
+REM   bin\tro_flow.bat --file mubea.csv
+REM   bin\tro_flow.bat --file mubea.csv --tosvg
+REM   bin\tro_flow.bat --file mubea.csv --tosvg --doc
+REM
+REM Die CSV-Datei wird in %SKEL_DATA% gesucht, DOT, SVG, Doku und
+REM Fehlerdatei werden in %SKEL_RESULTS% abgelegt.
+REM
+REM Schwesterprogramm: bin\material_flow.bat (Materialfluss der Objekte)
+REM ================================================================
+
+setlocal
+
+REM Umgebung setzen (SKEL_DATA, SKEL_RESULTS, SKEL_LIB, PYTHONPATH ...)
+call "%~dp0setenv.bat" >nul
+
+REM Virtuelle Umgebung nutzen, falls vorhanden (pydantic wird benoetigt)
+if exist "%SPS_SKEL%\.venv\Scripts\activate.bat" (
+    call "%SPS_SKEL%\.venv\Scripts\activate.bat"
+)
+
+REM Python-Interpreter bestimmen (py-Launcher bevorzugt, sonst python)
+set "PY=py"
+py --version >nul 2>&1 || set "PY=python"
+
+"%PY%" "%SKEL_LIB%\tro_flow.py" %*
+set "RC=%ERRORLEVEL%"
+
+endlocal & exit /b %RC%

bin/tro_flow.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# ================================================================
+# SPS_SKEL - TROs ermitteln und TRO-Flussdiagramm erzeugen
+# ================================================================
+# Aufruf:
+#   bash bin/tro_flow.sh --file mubea.csv
+#   bash bin/tro_flow.sh --file mubea.csv --tosvg
+#   bash bin/tro_flow.sh --file mubea.csv --tosvg --doc
+#
+# Die CSV-Datei wird in $SKEL_DATA gesucht, DOT, SVG, Doku und
+# Fehlerdatei werden in $SKEL_RESULTS abgelegt.
+#
+# Schwesterprogramm: bin/material_flow.sh (Materialfluss der Objekte)
+# ================================================================
+
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# Umgebung setzen (SKEL_DATA, SKEL_RESULTS, SKEL_LIB, PYTHONPATH ...)
+# shellcheck source=/dev/null
+. "$SCRIPT_DIR/setenv.sh" >/dev/null
+
+# Virtuelle Umgebung nutzen, falls vorhanden (pydantic wird benoetigt)
+if [ -f "$SPS_SKEL/.venv/bin/activate" ]; then
+    # shellcheck source=/dev/null
+    . "$SPS_SKEL/.venv/bin/activate"
+fi
+
+# Python-Interpreter bestimmen
+PY="python3"
+command -v python3 >/dev/null 2>&1 || PY="python"
+
+exec "$PY" "$SKEL_LIB/tro_flow.py" "$@"