test: Campaign LA finish LA2 probe and idle gates

Prove idle play remains passive and live until cancellation, then converges through one truthful status teardown. Keep probe mode string-only so numeric enum aliases cannot expand the pinned v1 contract, and record the Windows/WSL gates.

docs/plans/2026-08-14-launcher-campaign.md

@@ -478,7 +478,7 @@ LA6 adds CH-regression scrutiny; LA0 adds guard-integrity scrutiny.
 |---|---|---|---|---|
 | LA0 | **DONE 2026-08-14** | `cb6502c8`, `a49e92df` | Opus dual-lens PASS; all 6 findings CLOSED in narrow re-review | Byte-identity proven; Linux CI lanes restored; Platform BCL-only self-guard added; K0 guard untouched |
 | LA1 | implemented; Opus review in flight | `db9ad53c` (mixed — see `e1322a06`) | review in flight | Runtime 1630 / Headless 126 / App 5025+3skip / Core.Net 905 green; Runtime+Headless green on WSL; shared fixture parsed by BOTH host readers |
-| LA2 | — | | | |
+| LA2 | implementation complete; automated gates **GREEN**; Opus dual-lens review pending | `c6019424` + completion (this commit) | pending | Probe is roster-before-selection with graceful pre-world teardown and exit 0; normal play remains strict selector + `idle` policy. Release build green; Runtime 1,632/1,632 and Headless 141/141 on both Windows and Ubuntu/WSL |
 | LA3 | review FIX FIRST; fix round in flight | `37d74e44` + fixes pending | Opus 2026-08-14: 12 findings — 1 CRITICAL (`"paths": {}` breaks App loader), probe composition owed, Stop→SIGKILL hazard, 0600 temp window | Contract text now COMMITTED into LA1 section (review process note); cross-assembly loader test owed at LA1+LA3 merge; CI lane addition at merge |
 | LA4 | — | | | |
 | LA5 | — | | | |