feat: adapt review budget to diff size

pilot/review/opencode.py

@@ -440,7 +440,7 @@ def run_lenses_review(
     always has: prose + a final ```json fence with the legacy schema).
     """
     os.makedirs(WORK_ROOT, exist_ok=True)
-    budget = budget or Budget.from_config(config)
+    budget = budget or Budget.for_review(config, diff)
     budget_state = budget_state or BudgetState(budget)
     workdir = tempfile.mkdtemp(prefix=f"{repo.replace('/', '_')}-{sha[:8]}-", dir=WORK_ROOT)
     keep = bool(os.environ.get("PRAGENT_KEEP_WORK"))
@@ -687,7 +687,7 @@ def run(
             additional_context=additional_context,
         )
 
-    budget = Budget.from_config(config)
+    budget = Budget.for_review(config, diff)
     budget_state = BudgetState(budget)
     os.makedirs(WORK_ROOT, exist_ok=True)
     workdir = tempfile.mkdtemp(prefix=f"{repo.replace('/', '_')}-{sha[:8]}-", dir=WORK_ROOT)