feat(llvm): Phase 132-P2 - Dict ctx removal (FunctionLowerContext SSOT completion)

Completed SSOT unification for FunctionLowerContext by removing the manual
dict ctx creation and assignment in function_lower.py.

Changes:
- Removed builder.ctx = dict(...) creation (18 lines, lines 313-330)
- Removed builder.resolver.ctx assignment (no longer needed)
- Confirmed instruction_lower.py uses context=owner.context throughout
- Added phase132_multifunc_isolation_min.hako test for multi-function isolation
- Extended phase132_exit_phi_parity.sh with Case C (Rust VM context test)

Testing:
- Phase 132 smoke test: All 3 cases PASS
- Phase 87 LLVM exe test: PASS (Result: 42)
- STRICT mode: PASS
- No regressions: Behavior identical before/after (RC:6 maintained)

Impact:
- Reduced manual context management complexity
- FunctionLowerContext now sole source of truth (SSOT)
- Per-function state properly isolated, no cross-function collisions
- Cleaner architecture: context parameter passed explicitly vs manual dict

🤖 Generated with Claude Code
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

apps/tests/phase132_multifunc_isolation_min.hako

@@ -0,0 +1,29 @@
+// Phase 132-P2: Multi-function context isolation test
+// Tests that FunctionLowerContext properly isolates per-function state
+//
+// This creates two separate methods with independent loops to verify
+// that each function's context is cleaned up between calls.
+
+static box Main {
+    helper1(n) {
+        local i = 0
+        loop(i < n) {
+            i = i + 1
+        }
+        return i
+    }
+
+    helper2(n) {
+        local j = 0
+        loop(j < n) {
+            j = j + 1
+        }
+        return j
+    }
+
+    main() {
+        local a = helper1(2)
+        local b = helper2(3)
+        return a + b
+    }
+}