needs_replay: make simulated cases real aggregates, report buckets by state

A simulation that lives in JSON never meets the engine. needs_replay
takes a simulation's cases and runs them through the code the site
runs: answers::store_answer for the submission, aggregates::transition
for each desk move, against a real JetStream with its event log and
its refusal of undeclared moves. Buckets are then read back by
replaying each record's events and reported per bucket against
`done_when` and `success`. `--report-only` takes the same scorecard
from any JetStream, a live site's included.

First run, 30 cases from a generated contractor site on a throwaway
in-memory NATS: 30 aggregates, 56 transitions accepted, none refused.
The same routes against the earlier machine that skipped a stage: 8
refused, 8 of 12 enquiries left in `open`.

The local-checkout loaders move from the lint binary to `portal::local`
so both tools share them.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L4jrCgLiKKHAEFuZUJjckH

Cargo.toml

@@ -111,6 +111,11 @@ name = "question_lint"
 path = "src/bin/question_lint.rs"
 required-features = ["ssr"]
 
+[[bin]]
+name = "needs_replay"
+path = "src/bin/needs_replay.rs"
+required-features = ["ssr"]
+
 [profile.wasm-release]
 inherits = "release"
 opt-level = 'z'