Production pass: floats, GC, type checking, and tooling

Adds floats, bitwise ops, UTF-8 strings with methods, try/catch,
closures, generics validation, a compile-time type checker, a
mark-and-sweep GC, source-level debug info, constant folding, and
the repl/fmt/package-manager commands.

🤖 Generated with Codebuff
Co-Authored-By: Codebuff <noreply@codebuff.com>

examples/slicing.vr

@@ -0,0 +1,44 @@
+// array and string slicing: arr[1..3], arr[1:], str[0..5]
+
+fn main() {
+    // --- array slicing ---
+    let nums = [10, 20, 30, 40, 50]
+    
+    // basic slice: arr[start..end]
+    let mid = nums[1..3]
+    println(mid)          // [20, 30]
+    
+    // slice from start
+    let first_two = nums[0..2]
+    println(first_two)    // [10, 20]
+    
+    // slice to end (open-ended)
+    let tail = nums[2..]
+    println(tail)         // [30, 40, 50]
+    
+    // single element slice
+    let single = nums[3..4]
+    println(single)       // [40]
+    
+    // --- string slicing ---
+    let greeting = "hello, world!"
+    
+    // basic substring
+    let hello = greeting[0..5]
+    println(hello)        // "hello"
+    
+    // slice from index
+    let world = greeting[7..]
+    println(world)        // "world!"
+    
+    // slice to index
+    let hello_comma = greeting[0..6]
+    println(hello_comma)  // "hello,"
+    
+    // --- slicing in expressions ---
+    let data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+    let first = data[0..3]
+    let last = data[7..]
+    println(first)
+    println(last)
+}