feat: Phase 8.2, 8.4, 8.5, 9.1 + C backend fixes

Phase 8.2 — Gradual Ownership:
- Add tkRef/tkMutRef types and `mut` keyword
- Add @[Checked] attribute for opt-in borrow checking
- Reject assignment through &T in checked functions
- examples/ownership.bux

Phase 8.4 — CTFE:
- Evaluate const func at compile-time via evalExpr/evalBlock
- Fold const declarations to literals; emit #define in C
- examples/ctfe.bux (Factorial(10) → 3628800)

Phase 8.5 — Trait Bounds:
- Change declFuncTypeParams from seq[string] to seq[TypeParam] (name + bound)
- Parser handles <T: Comparable>
- Sema checks typeImplements at call sites
- Fix C backend: generic receivers + pointer self field access
- examples/trait_bounds.bux

Phase 9.1 — Package Manager:
- Inline tables/arrays in TOML parser
- bux add, bux install, bux.lock generation
- Dependency resolution with git/path sources
- Build pipeline merges dependency .bux sources

C Backend Fixes:
- resolveExprType(ekIdent) now applies typeSubst for generic params
- Method desugaring works for monomorphized generic receivers
- Pointer checks use isPointer (covers tkRef/tkMutRef)
- Field access on &T emits -> instead of .

Remove accidentally committed test binaries from tracking

src/parser.nim

@@ -212,6 +212,9 @@ proc parseBaseType(p: var Parser): TypeExpr =
     return TypeExpr(kind: tekPointer, loc: loc, pointerPointee: p.parseBaseType())
   of tkAmp:
     discard p.advance()
+    if p.check(tkMut):
+      discard p.advance()
+      return TypeExpr(kind: tekMutRef, loc: loc, pointerPointee: p.parseBaseType())
     return TypeExpr(kind: tekRef, loc: loc, pointerPointee: p.parseBaseType())
   of tkLParen:
     discard p.advance()
@@ -894,11 +897,27 @@ proc parseStmt(p: var Parser): Stmt =
 # Declarations
 # ---------------------------------------------------------------------------
 
-proc parseTypeParams(p: var Parser): seq[string] =
+proc parseTypeParams(p: var Parser): seq[TypeParam] =
   if p.check(tkLt):
     discard p.advance()
     while not p.check(tkGt) and not p.isAtEnd:
-      result.add(p.expect(tkIdent, "expected type parameter name").text)
+      let name = p.expect(tkIdent, "expected type parameter name").text
+      var bounds: seq[string] = @[]
+      if p.check(tkColon):
+        discard p.advance()
+        # Parse bound: single identifier or path like Std::Comparable
+        var boundName = ""
+        while true:
+          let part = p.expect(tkIdent, "expected trait/interface name").text
+          if boundName.len > 0:
+            boundName.add("_")
+          boundName.add(part)
+          if p.check(tkColonColon):
+            discard p.advance()
+          else:
+            break
+        bounds.add(boundName)
+      result.add(TypeParam(name: name, bounds: bounds))
       if p.check(tkComma):
         discard p.advance()
     discard p.expect(tkGt, "expected '>' to close type parameters")
@@ -1241,6 +1260,7 @@ proc parseDecl(p: var Parser): Decl =
   var attrs = ParsedAttrs()
   if p.check(tkAt):
     attrs = p.parseAttrs()
+  p.skipNewlines()
   
   var isConst = false
   if p.check(tkConst) and p.peek(1) == tkFunc: