harness(llvm/py): fix PHI/dominance via Resolver-only; per-pred localization and constant GEPs; stabilize Main.esc_json/1, dirname/1, node_json/3; docs: add NYASH_LLVM_TRACE_FINAL and Resolver-only invariants

- Resolver-only reads across BBs; remove vmap fallbacks
- Create PHIs at block start; insert casts in preds before terminators
- Re-materialize int in preds to satisfy dominance (add/zext/trunc)
- Use constant GEP for method strings to avoid order dependency
- Order non-PHI lowering to preserve producer→consumer dominance
- Update docs: RESOLVER_API.md, LLVM_HARNESS.md
- compare_harness_on_off: ON/OFF exits match; linking green

src/llvm_py/instructions/const.py

@@ -63,8 +63,12 @@ def lower_const(
         g.global_constant = True
         # Store the GlobalVariable; resolver.resolve_ptr will emit GEP in the current block
         vmap[dst] = g
-        if resolver is not None and hasattr(resolver, 'string_literals'):
-            resolver.string_literals[dst] = str_val
+        if resolver is not None:
+            if hasattr(resolver, 'string_literals'):
+                resolver.string_literals[dst] = str_val
+            # Mark this value-id as string-ish to guide '+' and '==' lowering
+            if hasattr(resolver, 'mark_string'):
+                resolver.mark_string(dst)
         
     elif const_type == 'void':
         # Void/null constant - use i64 zero