feat(compiler)!: add try-catch with C++ stack unwinding

Add TRY/CATCH/ENDTRY and anonymous THROW statements. Use LLVM exception
handling and the C++ ABI to propagate exceptions across function calls,
clean up catch state, and handle uncaught exceptions at the program boundary.
Register exception runtime symbols for the statically linked embedded runner.

Verify runtime checks, nested catches, returns, loops, and invalid syntax
with smoke programs; exercise unwinding with MCJIT, lli, and native binaries.

BREAKING CHANGE: Runtime check failures now throw anonymous exceptions and
print only a generic message when uncaught. Native binaries require linking
the C++ runtime.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/include/cps/FileHandler.h b/include/cps/FileHandler.h
index 3898a57..8b8ddf4 100644
--- a/include/cps/FileHandler.h
+++ b/include/cps/FileHandler.h
@@ -7,6 +7,7 @@
 namespace cps {
 
 class RuntimeCheck;
+class ExceptionHandler;
 
 // Emits the text-file runtime: a fixed-size open-file table plus internal
 // __cps_file_* helper functions, synthesized once on first use so programs
@@ -20,6 +21,7 @@ class FileHandler {
     llvm::IRBuilder<> &Builder;
     llvm::Module &Module;
     RuntimeCheck &Checker;
+    ExceptionHandler &Exceptions;
 
     static constexpr uint64_t TableSize = 16;
     bool RuntimeEmitted = false;
@@ -35,9 +37,6 @@ class FileHandler {
     llvm::GlobalVariable *FileModes = nullptr;   // [TableSize x i8]  0 = free slot, else FileMode
 
     llvm::Value *ModeReadStr = nullptr, *ModeWriteStr = nullptr, *ModeAppendStr = nullptr;
-    llvm::Value *ErrOpenFail = nullptr, *ErrAlreadyOpen = nullptr, *ErrTableFull = nullptr,
-                *ErrNotOpen = nullptr, *ErrNotRead = nullptr, *ErrNotWrite = nullptr,
-                *ErrPastEof = nullptr;
 
     // synthesized helpers (internal linkage; pseudocode identifiers cannot
     // start with '_', so these names are un-collidable)
@@ -60,7 +59,7 @@ class FileHandler {
 
 public:
     FileHandler(llvm::LLVMContext &Ctx, llvm::IRBuilder<> &B, llvm::Module &M,
-                RuntimeCheck &RC);
+                RuntimeCheck &RC, ExceptionHandler &EH);
 
     // NameStr/DataStr are already-coerced STRING ptrs; Line is the statement's
     // source line for runtime diagnostics. All methods null-check and bail;