green(reify): type-fn bodies comptime-evaluated; reify fully removed from the compiler

Second slice of the re-architecture — the compiler now has ZERO type-
construction code beyond declare/define.

- instantiateTypeFunction: a type-fn body returning a computed Type (a call
  to a non-generic, bodied, Type-returning fn) is comptime-evaluated with the
  type bindings active, then renamed to the mangled instantiation name for
  identity (renameNominalType). Replaces the old reify-call pattern-matching.
- DELETED: reifyType (lower/nominal.zig), findReturnReifyCall (lower/generic.zig),
  and the stale inline-position reify gate in resolveTypeCallWithBindings.
- evalComptimeType (was evalComptimeTypeNamed): pure eval, no rename; the
  type-fn caller renames explicitly. renameReifiedType → renameNominalType.
- The TYPE NAME now travels in the data: EnumInfo gains `name`, and define()
  names the slot from it (the compiler derives no name from a binding LHS).
  examples/0614/0615 carry `name = "..."`; RecvResult/TryResult set it too.
- field_type stays a reflection #builtin (reads a type); only construction
  moved out. All reify mentions stripped from compiler source.

examples 0614/0615/0617 run on the floor. Full suite green (673).

src/ir/inst.zig

@@ -449,15 +449,16 @@ pub const BuiltinId = enum(u16) {
     type_eq,
     type_is_unsigned,
     has_impl,
-    // Comptime type CONSTRUCTION (REIFY floor). The compiler's ONLY
-    // type-minting primitives — `reify` / `make_enum` / `RecvResult` etc.
-    // are sx in `meta.sx`, built over these. Both are comptime-only (the
-    // interp mutates the type table via its `mint` handle); reaching them
-    // at runtime / emit is a hard error.
-    //   declare()            → mint an EMPTY (undefined) nominal slot, return
-    //                          it as a `Type` value. Using the slot before
-    //                          `define` is a loud diagnostic (F5).
-    //   define(handle, info) → decode the `TypeInfo` VALUE + complete the slot.
+    // The compiler's ONLY comptime type-CONSTRUCTION primitives. Higher-level
+    // constructors (one-shot, channel-result, etc.) are ordinary sx built over
+    // these — the compiler knows none of them by name. Both are comptime-only
+    // (the interp mutates the type table via its
+    // `mint` handle); reaching them at runtime / emit is a hard error.
+    //   declare()            → mint an EMPTY (undefined) nominal slot, returned
+    //                          as a `Type` value. Using the slot before its
+    //                          `define` is a loud diagnostic.
+    //   define(handle, info) → decode the `TypeInfo` VALUE (the name travels in
+    //                          it) and complete the slot.
     declare,
     define,
 };