test(e2e): consolidate automine contracts and effects suites

[spalladino]

Round-2 e2e consolidation (PR 2 of 9), scoped to automine/contracts/**, automine/effects/**, automine/accounts/scope_isolation.test.ts, and automine/mempool_limit.test.ts. All 8 touched files pass locally.

Merges (old → new)

• effects/{event_only.test.ts, custom_message.parallel.test.ts, large_public_event.test.ts} → effects/events.test.ts — one beforeAll node, per-contract describe blocks. custom_message loses its .parallel suffix (bodies are tiny; one container is a net win). 3 files → 1.
• contracts/nested/{manual_private_call.test.ts, manual_public.parallel.test.ts, manual_private_enqueue.parallel.test.ts} → contracts/nested/manual_calls.test.ts — single beforeAll deploying a shared Parent/Child; the public and enqueued-call suites redeploy a fresh Child per test because each asserts an absolute post-increment storage value that only holds from a zero start. 3 files → 1.

Table / de-parallel conversions

• accounts/scope_isolation.test.ts — the external private / external utility describes (structural duplicates differing only by a _utility method suffix) collapsed via describe.each.
• contracts/option_params.parallel.test.ts → contracts/option_params.test.ts (plain) + it.each over the public/utility/private variants.
• contracts/nested_utility_calls.parallel.test.ts → contracts/nested_utility_calls.test.ts (plain). See decision below.

nested_utility_calls decision

The file has two describes with genuinely different setups — the first uses a plain PXE, the second registers a custom pxeCreationOptions.hooks.authorizeUtilityCall. Per-container isolation was not the point (all bodies are fast simulate() calls with no cross-test shared state; the hook describe already resets its state in beforeEach), so I converted it to a single plain file with both describes, each keeping its own beforeAll (two sequential node bootstraps in one container — a CPU win over the previous 14 per-it containers). Within the hook describe the deny/allow × utility/private/view sextet is now an it.each; the two default-deny cases in the first describe are also tableized. The msg_sender and note-sync tests stay explicit. Runs in well under the container timeout locally.

Added assertions for previously zero-assertion its

• manual_calls "performs a nested private call": now simulates parent.entry_point → child.value(0) and asserts it returns the same preimage as a direct child.value(0) call, in addition to sending the tx for on-chain inclusion.
• manual_calls "performs public nested calls": now routes pub_entry_point → pub_inc_value(42) on a fresh child and asserts child storage is 42 (was assertion-free).
• importer.parallel (stays .parallel, titles unchanged): call_no_args asserts the imported call returns the Test contract address; call_public_fn and pub_call_public_fn assert the nullifier landed by checking that re-emitting it on the Test contract is rejected as a duplicate.

Other

• contracts/state_vars.test.ts: extracted a file-local expectInitialized(interaction, expected) helper replacing ~15 repeated is_*_initialized simulate+expect blocks.
• mempool_limit.test.ts: removed the explicit no-op proverTestVerificationDelayMs: undefined option.

Dropped assertions

None. Every asserted behavior is preserved; the zero-assertion its gained real assertions rather than losing any. Test discovery and the compat suite are glob-based, so no bootstrap.sh / .test_patterns.yml edits were needed.