Make the module-loading contract origin-aware so group-owned modules
become resolvable and imports can resolve lexically (§5.5).
- `ModuleScript` gains a polymorphic owner (`app_id`/`group_id` + `owner()`),
mirroring `Script`.
- `ModuleSource::lookup(&cx, name)` -> `resolve(origin: ScriptOwner, name)`:
resolution walks the group chain rooted at the importing script's
defining node (nearest-owner-wins), not the inheriting app's view.
- `PostgresModuleSource::resolve` branches on origin: app-rooted
(`CHAIN_LEVELS_CTE`) or a new group-rooted `GROUP_CHAIN_LEVELS_CTE`,
joining `kind='module'` rows.
The executor resolver passes a temporary `App(cx.app_id)` origin (behaviour-
preserving for app scripts; true lexical origin lands in C3). Group scripts
still can't carry imports until C4, so no trust-inversion window opens here.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>