PvZ storm observation

Adventure 4-10 uses lightning and darkness rather than the ordinary fog mask. Older clients supplied concealed enemy counts and positions. The optional storm-observation-v1 capability accepts a measured glimpse or obscured state only on Adventure 4-10. Obscured snapshots cannot contain enemy sightings.

Dave and plants receive unknown counts/positions during darkness or from an older unmeasured storm client. A measured glimpse retains existing named, one-based sightings. Prompt projection never mutates the native request used for action validation. Other chapters, account settings, saves and database schema are unchanged. No UI instructions about AI measurement are added.

Verification: failing regressions followed by 496 passing isolated NPC tests; hosted pnpm build, pnpm typecheck, and pnpm oss:verify pass. The new native candidate also passes 98 visibility checks, 710 web tests and real compiled EN desktop/ZH touch-emulated storm openings. The first draft non-storm test fixture used unsupported plant identity fields; the corrected fixture removes them. No full storm victory, paid-provider writing or physical-phone claim.

Deploy this host capability before the separately packaged native client. Older clients remain compatible and their unmeasured storm data is withheld.