Multiple extends clauses not supported

[AntoineGautier]

When a Modelica class contains multiple extends clauses, LongClass in parser.ts only retains the last one. The extendElement, mods, and extendElementDeadEnd fields are overwritten on each iteration, so all but the last extends clause are dropped.

Affected Code

server/src/parser/parser.ts — LongClass constructor, where extends_clause entries are processed:

// Current behavior: each extends overwrites the previous
this.extendElement = ...
this.mods = ...

getChildElements() only walks one inheritance chain.

getInputs() misses parameters from all but the last extends parent.

Proposed Fix

Replace the scalar extendElement / mods fields with arrays (extendElements, extendMods) and update all consumers (getChildElements, getInputs, schedule.ts) to iterate over all entries.