Well Event: Emit RPTRST/RPTSCHED as proper mnemonic lists

Schedule-level keywords whose OPM ParserRecord is a single ALL-sized item
(RPTRST, RPTSCHED, ...) are not positional — they take a free-form list
of mnemonic tokens like `BASIC=2 DEN ROCKC NORST=1`. Previously each
`keyword_data` entry became its own DeckItem, and OPM emitted them
either as truncated positional values or as a quoted, space-collapsed
single string.

Detect that schema shape in `RifEventKeywordFormatter::formatKeyword`
and pack the user's entries into one RawString DeckItem of mnemonic
tokens: `KEY` for FLAG items, `KEY=VALUE` otherwise.

To distinguish flag mnemonics (`DEN`) from `KEY=1`-style entries, add a
new `FLAG` value to `RimWellEventKeywordItem::ItemType` plumbed end to
end (Python -> GRPC -> Rimc -> storage -> formatter). The Python API
now maps `bool True` to FLAG and silently drops `bool False`.

For positional keywords (WCONHIST etc.) FLAG items have no value to
emit and are rendered as default markers ("1*").

A `rawStringItem` helper is added to `RifOpmDeckTools` so the
mnemonic-list path can produce DeckItems whose OPM output is not
quoted.

ApplicationLibCode/ProjectDataModelCommands/RimcWellEventTimeline.cpp

@@ -406,9 +406,13 @@ std::expected<caf::PdmObjectHandle*, QString> RimcWellEventTimeline_addWellKeywo
             }
             event->addDoubleItem( name, doubleValue );
         }
+        else if ( type == "FLAG" )
+        {
+            event->addFlagItem( name );
+        }
         else
         {
-            return std::unexpected( QString( "Unknown item type: %1. Must be STRING, INT, or DOUBLE" ).arg( type ) );
+            return std::unexpected( QString( "Unknown item type: %1. Must be STRING, INT, DOUBLE, or FLAG" ).arg( type ) );
         }
     }
 
@@ -498,9 +502,13 @@ std::expected<caf::PdmObjectHandle*, QString> RimcWellEventTimeline_addKeywordEv
             }
             event->addDoubleItem( name, doubleValue );
         }
+        else if ( type == "FLAG" )
+        {
+            event->addFlagItem( name );
+        }
         else
         {
-            return std::unexpected( QString( "Unknown item type: %1. Must be STRING, INT, or DOUBLE" ).arg( type ) );
+            return std::unexpected( QString( "Unknown item type: %1. Must be STRING, INT, DOUBLE, or FLAG" ).arg( type ) );
         }
     }