Make `check` mean "will compile"

[zharinov]

Problem

check exit 0 does not mean the query can be compiled and executed. Confirmed counterexamples:

• Q = (program (comment)? (comment)? (comment)?) — check passes, dump/exec/infer panic (IR passes don't preserve successor order, and collapse_prefix has soundness holes #421, item 1).
• A 300-capture query — check passes, struct field count silently wraps mod 256 (Binary format fails open: no validation on load, unchecked capacity casts #422, item 4).

• 1023 effect payloads — check passes, emit asserts (Binary format fails open: no validation on load, unchecked capacity casts #422).

Users and editor integrations treat check as the gate. Everything reachable from a check-clean query should either work or have been rejected by check.

Approach

Two options, not mutually exclusive:

1. Make check run the full pipeline — compile + emit, discarding the output. Honest by construction; costs compile time on large queries.
2. Lift the failure modes into analyze so they're proper diagnostics (capacity limits are countable statically; pass soundness is IR passes don't preserve successor order, and collapse_prefix has soundness holes #421's job).

Either way, the contract becomes a property test in the conformance layer (#418): if check passes, emit() succeeds and the output validates.