iter mq.3: retire MethodNameCollision + multi-class E2E + DESIGN.md sync

Closes the module-qualified-class-names milestone. Deletes the
workspace-load workaround; the two-libraries case now resolves via
type-driven dispatch at the call site with explicit qualifier as the
LLM-author's disambiguation tool. Resolves both mq.2 known-debt items
(active_declared_constraints plumbing, (class,method) re-key). New
synth warnings channel emits class-method-shadowed-by-fn at all three
fn-precedence branches per spec section Class-fn collisions. Three new
E2E fixtures + integration tests cover the ambiguous, qualified, and
class-fn-shadow trajectories. DESIGN.md class-names paragraph rewritten,
new section Method dispatch added. Roadmap P2 marked done, milestone-24
unblocked for re-brainstorm.

9/9 tasks. 545 tests green. bench/compile_check.py + cross_lang.py
exit 0; bench/check.py exit 1 (2 noise-class regressions, runtime
uncoupled to typecheck iter).

bench/orchestrator-stats/2026-05-13-iter-mq.3.json

@@ -0,0 +1,22 @@
+{
+  "iter_id": "mq.3",
+  "date": "2026-05-13",
+  "mode": "standard",
+  "outcome": "DONE",
+  "tasks_total": 9,
+  "tasks_completed": 9,
+  "reloops_per_task": {
+    "1": 0,
+    "2": 0,
+    "3": 0,
+    "4": 0,
+    "5": 0,
+    "6": 0,
+    "7": 0,
+    "8": 0,
+    "9": 0
+  },
+  "review_loops_spec": 0,
+  "review_loops_quality": 0,
+  "blocked_reason": null
+}