PvZ bitten-plant conversation observations

The source engine can remove a living shooter's or Sunflower's head while leaving its health unchanged. Previously, Dave and plant conversations received only species and health, so the supplied context could not distinguish that disabled plant from a functioning one.

The optional planted[].headMissing: true observation now carries the actual native condition for supported authored chapters. The shared schema requires the matching source chapter, full living identity and a removable-head species. It rejects classic, dead, untyped and mismatched claims. Existing requests without the field remain valid. The new source-plant-head-v1 configuration capability lets the game omit the field for older hosts.

Dave's lawn context, visible defenses and the selected plant's own context explain the same consequence: no new shots, or no sun production for a Sunflower. Existing shots remain independent. Health, affection and cosmetic naming do not regrow a head. The observation does not establish who bit the plant or when, so it supplies no invented blame or past event. This adds no action authority, rewards, stored state, new pauses or UI copy.

Verification: the new tests failed against the prior schema; 512 isolated game-NPC tests pass after implementation, along with the hosted build and all eight typecheck tasks. Browser/native integration is tracked in the game worktree's docs/plant-head-observations-2026-09-23.md. No production database changes are required. This report does not claim a particular live provider's generated wording.