comptime VM: flip Type to .type_value; migrate the .any refs that mean a Type value

type_resolver "Type" -> .type_value; const_type result + emitConstType now a
bare 8-byte i64 handle (not a 16-byte Any box). Migrated every .any ref meaning
"a Type value", leaving real boxed-Any refs:

- "Any holds a Type" meta-marker tag .any -> .type_value at all 4 consumers
  (reflectArgTypeId, reflectTypeId, the comptime type_tag-as-struct path,
  resolveTypeCategoryTags "type").
- reflection-builtin return types (type_of/declare/define) -> .type_value;
  runtime type_of(any) reads the tag as a .type_value (no re-box).
- expr_typer: a bare type-name expr is .type_value (backtick is_raw exempt).
- reflectionArgIsType accepts .type_value OR .any (a reflection arg can be a
  bare Type or a boxed Any).
- comptime switch_br accepts a .type_tag discriminant (type-category match).
- a bare function name in a Type slot -> const_type(its function type), not a
  func-ref (fixes a JIT crash); old string-box kept only for genuine Any params.
- field-not-found diagnostic + formatTypeName render .type_value as "Type".

Fixed 3 unit tests asserting the old .any behavior. 697/0 both gates (gate ON
bails cleanly to legacy since the VM doesn't model Type values yet) + 494 unit
tests. 24 snapshots regenerated (22 .ir const_type shape; 2 .stderr Any->Type).

src/ir/module.zig

@@ -454,11 +454,12 @@ pub const Builder = struct {
     /// fail loudly rather than silently materialise the TypeId as an
     /// int.
     pub fn constType(self: *Builder, tid: TypeId) Ref {
-        // Type values are Any-shaped at runtime —
-        // `{ tag = .any.index() (the meta-marker), value = tid }`.
-        // Matches `Type → .any` in `type_bridge`. The interp keeps
-        // the high-fidelity `.type_tag` Value for comptime ops.
-        return self.emit(.{ .const_type = tid }, .any);
+        // A Type value is its own 8-byte builtin handle (`.type_value`), a bare
+        // i64 carrying `tid.index()` — distinct from the 16-byte boxed `.any`.
+        // Flowing it into an `Any` slot boxes it (`{ tag = .any.index(), value =
+        // tid }`) via the standard box-any coercion. The interp keeps the
+        // high-fidelity `.type_tag` Value for comptime ops.
+        return self.emit(.{ .const_type = tid }, .type_value);
     }
 
     // ── Arithmetic ──────────────────────────────────────────────────