fix: address Miden Bank tutorial feedback from review

[Keinberger]

Context

Consolidates Miden Bank tutorial feedback from two reviewers:

• Dominik's review in miden-devrel#126 (comments from Mar 9 and Mar 10)
• PhilippGackstatter's detailed audit in docs#203

Blockers (tests that don't compile)

1. Part 3: Test references deposit-note which doesn't exist until Part 4
2. Part 4: Test references init-tx-script which doesn't exist until Part 6
3. Part 6: Possible no field 'dep' compiler error (needs verification)

Security concerns

4. Withdraw note passes sender explicitly as depositor param, an attacker could pass a victim's ID
5. No overflow check on current_balance + deposit_amount in deposit
6. No validation that asset is fungible before accessing inner[0]

Important accuracy fixes

7. Part 0 Step 4 Cargo.toml update is a no-op
8. Part 1 re-adds balances: StorageMap already present from Part 0
9. Part 5 WIT file listing shows wrong filenames
10. "Auto-assigns slot numbers based on field order" is outdated
11. StorageMap::get return type claimed as Felt but returns any type convertible from Word
12. "Called by other contracts" should be "Called by other components"
13. Part 7 re-introduces withdraw() already in Part 3
14. Cross-component explanation (Part 5) comes AFTER Part 4 already uses it
15. Key layout should use little-endian for 0.14 compatibility

Minor / cosmetic

16. Part 2 test description mismatch (says "verifies deposit without init fails" but never calls deposit)
17. require_initialized introduced too early (Part 1, not called until Part 2)
18. Cargo.toml updates in Parts 4, 6, 7 are all no-ops
19. Trace log spam not shown in expected output
20. Typo "from outside" -> "from the outside"
21. Part 5 bindings visualization arrow unclear
22. No IDE support note for contracts excluded from workspace
23. Part 1 MockChain claim but no MockChain created