feat: 7.15 features -- ZcashDisplayAddress, AdvancedMode gates, blind-sign policy

Solana (+11 tests → 23 total):
- 4 negative/rejection: malformed, truncated, trailing bytes, oversized
- 2 multi-instruction: 2x transfer, transfer+memo
- 1 token metadata: SolanaTokenInfo with USDC mint/symbol/decimals
- 2 path edge cases: 3-element path, wrong coin type
- 1 versioned v0: opaque tx requiring AdvancedMode
- 1 already existed: sign_message_blocked_without_advanced_mode

TRON (+6 tests → 15 total):
- 2 path edge cases: too short (2 levels), wrong coin type
- 2 negative: empty raw_data, oversized raw_data
- 1 determinism: same raw_data produces same signature
- 1 different accounts: different keys produce different signatures

TON (+9 tests → 20 total):
- 2 path edge cases: too short (2 levels), wrong coin type
- 2 negative: empty raw_tx, oversized raw_tx
- 2 memo edge cases: empty memo, long memo (255 chars)
- 2 workchain: explicit zero, default (verify match)
- 1 different accounts: different keys produce different signatures

Also: removed duplicate test_tron_show_address and test_ton_show_address

- test_ton_path_too_short: firmware is lenient (accepts 2-level path)
- test_ton_path_wrong_coin: firmware rejects wrong coin type (expect CallException)
- test_tron_path_wrong_coin: firmware rejects wrong coin type (expect CallException)
- test_tron_sign_deterministic: fix assertEqual arity (use assertTrue instead)

…ddress)

1. N5 method name: test_ton_sign_with_comment -> test_ton_sign_with_memo (JUnit match)
2. N4 description: remove false "hash verification" claim, describe actual behavior
3. S12: add token_info metadata test (SolanaTokenInfo with USDC mint/symbol)
4. TON section description: remove cell tree reconstruction claim (deferred to 7.15)
5. TON bullet points: CLEAR-SIGN -> STRUCTURED (accurate for current behavior)
6. S5 description: add AdvancedMode requirement note
7. T4 description: clarify blind sign shows amount+address if provided

…ce + raw_address bug

feat: expanded test coverage for Solana, TRON, TON (58 tests)