Scripting: list a folio's conductors by uuid and find their ends

A script could name a conductor only by one of its ends, "the conductor on
terminal N of element X", which fails where two conductors meet at one
terminal and cannot follow a conductor that is re-connected.

qet.conductorUuids(folio) lists the folio's conductor uuids, in the order
qet.conductors() lists them. qet.conductorEnds(folio, uuid) returns that
conductor's two ends as "{element uuid} terminal N" -- the form
conductors() prints and the conductor calls take -- or an empty list if
the folio has no such conductor. The end formatting conductors() already
did is shared rather than copied.

Conductors of older projects have no saved uuid yet, so theirs change
from one load to the next until that is settled (discussion #1103); new
conductors keep theirs.

tst_scriptconductoruuid runs a script through --run on a fixture: every
conductor has a distinct uuid, and its ends match the conductors() line
at the same position; an unknown uuid, a malformed one and a folio that
does not exist give empty lists. It fails with the two ends swapped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/scripting/qetscriptapi.h

@@ -396,6 +396,8 @@ class QetScriptApi : public QObject
 
 		// -- conductor properties, applied to the whole potential --
 		Q_INVOKABLE QStringList conductors(int folioIndex) const;
+		Q_INVOKABLE QStringList conductorUuids(int folioIndex) const;
+		Q_INVOKABLE QStringList conductorEnds(int folioIndex, const QString &uuid) const;
 		Q_INVOKABLE QString conductorProperty(int folioIndex, const QString &elementUuid,
 											  int terminalIndex, const QString &property) const;
 		Q_INVOKABLE bool setConductorProperty(int folioIndex, const QString &elementUuid,