Compiler errors should not be rendered as exceptions

Properly formed errors should be errors, not exceptions with full stack trace.

Example I've got from Cesium SDK:
```
0>------- Started building project: Tabularius.Interop.Dto
CONSOLE: Generating assembly "obj\Debug\net10.0\Tabularius.Interop.Dto.dll".
CONSOLE: Processing source file "G:\Projects\tabularius\Tabularius.Interop.Dto\lib.c".
CONSOLE: Unhandled exception. Cesium.Core.CompilationException: Cannot resolve type Quantity
CONSOLE: at Cesium.CodeGen.Contexts.TranslationUnitContext.ResolveType(IType type, ImmutableArray`1 resolutionStack) in /_/Cesium.CodeGen/Contexts/TranslationUnitContext.cs:line 187
CONSOLE: at Cesium.CodeGen.Contexts.TranslationUnitContext.<>c__DisplayClass35_1.b__2(LocalDeclarationInfo structMember) in /_/Cesium.CodeGen/Contexts/TranslationUnitContext.cs:line 264
CONSOLE: at System.Linq.Enumerable.ListSelectIterator`2.Fill(ReadOnlySpan`1 source, Span`1 destination, Func`2 func)
CONSOLE: at System.Linq.Enumerable.ListSelectIterator`2.ToList()
CONSOLE: at Cesium.CodeGen.Contexts.TranslationUnitContext.<>c__DisplayClass35_0.g__ResolveStructMembers|0(StructType structType) in /_/Cesium.CodeGen/Contexts/TranslationUnitContext.cs:line 261
CONSOLE: at Cesium.CodeGen.Contexts.TranslationUnitContext.ResolveType(IType type, ImmutableArray`1 resolutionStack) in /_/Cesium.CodeGen/Contexts/TranslationUnitContext.cs:line 237
CONSOLE: at Cesium.CodeGen.Contexts.TranslationUnitContext.ResolveType(IType type) in /_/Cesium.CodeGen/Contexts/TranslationUnitContext.cs:line 180
CONSOLE: at Cesium.CodeGen.Contexts.GlobalConstructorScope.ResolveType(IType type) in /_/Cesium.CodeGen/Contexts/GlobalConstructorScope.cs:line 63
CONSOLE: at Cesium.CodeGen.Ir.Lowering.BlockItemLowering.Lower(IDeclarationScope scope, IBlockItem blockItem)
CONSOLE: at Cesium.CodeGen.Ir.Lowering.BlockItemLowering.LowerDeclaration(IDeclarationScope scope, IBlockItem blockItem) in /_/Cesium.CodeGen/Ir/Lowering/BlockItemLowering.cs:line 75
CONSOLE: at Cesium.CodeGen.Contexts.AssemblyContext.<>c__DisplayClass29_0.b__0(IBlockItem node) in /_/Cesium.CodeGen/Contexts/AssemblyContext.cs:line 68
CONSOLE: at System.Linq.Enumerable.IteratorSelectIterator`2.ToListNoPresizing()
CONSOLE: at System.Linq.Enumerable.IteratorSelectIterator`2.ToList()
CONSOLE: at Cesium.CodeGen.Contexts.AssemblyContext.EmitTranslationUnit(String name, TranslationUnit translationUnit) in /_/Cesium.CodeGen/Contexts/AssemblyContext.cs:line 68
CONSOLE: at Cesium.Compiler.Compilation.GenerateCode(AssemblyContext context, AbsolutePath inputFile) in /_/Cesium.Compiler/Compilation.cs:line 165
CONSOLE: at Cesium.Compiler.Compilation.Compile(IEnumerable`1 inputFilePaths, LocalPath outputFile, CompilationOptions compilationOptions) in /_/Cesium.Compiler/Compilation.cs:line 82
CONSOLE: at Cesium.Compiler.Program.<>c.<b__0_0>d.MoveNext() in /_/Cesium.Compiler/Main.cs:line 62
CONSOLE: --- End of stack trace from previous location ---
CONSOLE: at Cesium.Compiler.CommandLineParser.<>c__DisplayClass0_0.<b__1>d.MoveNext() in /_/Cesium.Compiler/CommandLineParser.cs:line 41
CONSOLE: --- End of stack trace from previous location ---
CONSOLE: at Cesium.Compiler.CommandLineParser.ParseCommandLineArgs(String[] args, ICompilerReporter reporter, Func`2 worker) in /_/Cesium.Compiler/CommandLineParser.cs:line 22
CONSOLE: at Cesium.Compiler.Program.Main(String[] args) in /_/Cesium.Compiler/Main.cs:line 18
CONSOLE: at Cesium.Compiler.Program.(String[] args)
```

Reproduce the unresolved-type case shown in the issue, then start with the error flow through Cesium.Compiler/Main.cs, CommandLineParser.cs, and Compilation.cs. Trace how CompilationException reaches the command-line reporter and adjust the handling so a properly formed compiler error is reported without a full exception stack trace. Done means the diagnostic remains visible while the stack trace is absent.

Written by the indexing model from the issue text.