wip(0.S3): ui blocks, scene on enter/exit, hooks, machines over a state's field, namespace and engine-system injection; a reference out of a read-only state or a module let is read-only; deps counts writes into another module's state; the rejected examples hold states

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/rejected/private_bank/ledger.ludic

@@ -1,13 +1,15 @@
 # bank/ledger.ludic - inherits `module bank` from the barrel that imports it
-var balance: int = 0
-export event Deposited { amount: int }
-function add(n: int) -> void {
-  balance += n
+export state BankState {
+  balance: int = 0
 }
-export function deposit(n: int) -> void {
-  add(n)
+export event Deposited { amount: int }
+function add(bank_st: mut BankState, n: int) -> void {
+  bank_st.balance += n
+}
+export function deposit(bank_st: mut BankState, n: int) -> void {
+  add(bank_st, n)
   emit Deposited(amount: n)
 }
-export function total() -> int {
-  return balance
+export function total(bank_st: BankState) -> int {
+  return bank_st.balance
 }