fix: register transaction routes independently

[tolga-tom-nook]

Summary

Fixes transaction route registration so transaction endpoints are controlled by the transaction option instead of being accidentally nested under blocks_data.

Before this change, when transaction=on and blocks_data=off, only the block transaction-list routes were registered. The core transaction lookup/proof endpoints were skipped because their if app["transaction"] blocks were indented inside the previous if app["blocks_data"] block.

Impact

With transaction=on and blocks_data=off, these routes now register as expected:

• GET /rest/transaction/{tx_pointer}
• GET /rest/transaction/hash/by/pointer/{tx_blockchain_pointer}
• GET /rest/transaction/calculate/merkle_proof/{tx_pointer}
• GET /rest/transaction/merkle_proof/{tx_pointer}
• POST /rest/transactions/by/pointer/list
• POST /rest/transactions/hash/by/blockchain/pointer/list

Validation

RED check before the fix showed only 2 transaction-related routes when blocks_data=False; after the fix the full transaction endpoint set is present.

Commands run after the fix:

PYTHONDONTWRITEBYTECODE=1 python3 - <<'PY'
import ast, pathlib
for p in pathlib.Path('.').rglob('*.py'):
    if '__pycache__' not in p.parts:
        ast.parse(p.read_text(), filename=str(p))
print('Python AST syntax OK')
PY

PYTHONDONTWRITEBYTECODE=1 python3 -m pytest tests/test_route_registration.py -q

git diff --check

Result:

Python AST syntax OK
1 passed in 0.02s
git diff --check: clean

Bounty context: Bitgesell PR bounty program / improvement bounty.

[MyTH-zyxeon]

Review assist for maintainers:

This looks like a focused route-registration fix: the transaction and transactions route blocks are now registered independently when app["transaction"] is enabled, instead of being nested under the preceding route section. The added test loads api/routes.py with stubbed handler symbols and verifies the transaction paths are present even when unrelated feature flags such as blocks_data are disabled.

Suggested merge checks:

• Run the new route-registration test and one existing app startup/import smoke test to confirm the AST/stub-loader test still reflects real handler names.
• Exercise setup_routes with transaction=True, blocks_data=False, and both merkle_proof=True/False so the /rest/transaction/merkle_proof/{tx_pointer} fallback behavior stays intentional.
• Confirm no transaction route is now registered twice when all feature flags are enabled.

I do not see database, wallet/key, RPC, or live-chain behavior changes in this patch as written; the main acceptance criterion is that transaction routes are gated only by transaction and no longer disappear behind unrelated feature toggles.