feat(modules): owner-aware module lookup — lexical chain walk (Phase 4b C1)

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>

crates/executor-core/src/module_resolver.rs

@@ -319,8 +319,19 @@ impl ModuleResolver for PicloudModuleResolver {
             ))
         })?;
 
+        // C1 (Phase 4b): resolve via the owner-aware `resolve`. Until C3
+        // threads the importing script's true defining node through, the
+        // origin is the calling app — behaviour-preserving for app-owned
+        // scripts (group scripts can't yet carry imports). The app-rooted
+        // chain walk additionally lets an app import an ancestor group's
+        // modules, which is the intended Phase 4b capability.
         let lookup_result: Result<Option<picloud_shared::ModuleScript>, ModuleSourceError> =
-            tokio::task::block_in_place(|| handle.block_on(self.source.lookup(&self.cx, path)));
+            tokio::task::block_in_place(|| {
+                handle.block_on(
+                    self.source
+                        .resolve(picloud_shared::ScriptOwner::App(self.cx.app_id), path),
+                )
+            });
 
         let module_row = match lookup_result {
             Ok(Some(m)) => m,

crates/executor-core/tests/module_redaction_logging.rs

@@ -16,7 +16,7 @@ use picloud_executor_core::{Engine, ExecRequest, InvocationType, Limits};
 use picloud_shared::{
     AppId, ExecutionId, ModuleScript, ModuleSource, ModuleSourceError, NoopDeadLetterService,
     NoopDocsService, NoopEventEmitter, NoopHttpService, NoopKvService, RequestId, ScriptId,
-    ScriptSandbox, SdkCallCx, Services,
+    ScriptOwner, ScriptSandbox, Services,
 };
 use serde_json::Value;
 use tracing_subscriber::fmt::MakeWriter;
@@ -27,9 +27,9 @@ struct FailingSource;
 
 #[async_trait]
 impl ModuleSource for FailingSource {
-    async fn lookup(
+    async fn resolve(
         &self,
-        _cx: &SdkCallCx,
+        _origin: ScriptOwner,
         _name: &str,
     ) -> Result<Option<ModuleScript>, ModuleSourceError> {
         Err(ModuleSourceError::Backend(SENTINEL.to_string()))

crates/executor-core/tests/modules.rs

@@ -18,7 +18,7 @@ use picloud_executor_core::{Engine, ExecRequest, InvocationType, Limits};
 use picloud_shared::{
     AppId, ExecutionId, ModuleScript, ModuleSource, ModuleSourceError, NoopDeadLetterService,
     NoopDocsService, NoopEventEmitter, NoopHttpService, NoopKvService, RequestId, ScriptId,
-    ScriptSandbox, SdkCallCx, Services,
+    ScriptOwner, ScriptSandbox, Services,
 };
 use tokio::sync::Mutex;
 
@@ -55,7 +55,8 @@ impl CountingModuleSource {
             (app_id, name.to_string()),
             ModuleScript {
                 script_id,
-                app_id,
+                app_id: Some(app_id),
+                group_id: None,
                 name: name.to_string(),
                 source: source.to_string(),
                 updated_at,
@@ -71,20 +72,27 @@ impl CountingModuleSource {
 
 #[async_trait]
 impl ModuleSource for CountingModuleSource {
-    async fn lookup(
+    async fn resolve(
         &self,
-        cx: &SdkCallCx,
+        origin: ScriptOwner,
         name: &str,
     ) -> Result<Option<ModuleScript>, ModuleSourceError> {
         self.lookups.fetch_add(1, Ordering::SeqCst);
         if let Some(err) = self.fail_with.lock().await.as_ref() {
             return Err(ModuleSourceError::Backend(err.clone()));
         }
+        // This fake is flat/app-scoped — the inheritance + lexical
+        // resolution semantics are covered by the CLI journey tests
+        // against real Postgres. A group origin has no entries here.
+        let app_id = match origin {
+            ScriptOwner::App(a) => a,
+            ScriptOwner::Group(_) => return Ok(None),
+        };
         Ok(self
             .table
             .lock()
             .await
-            .get(&(cx.app_id, name.to_string()))
+            .get(&(app_id, name.to_string()))
             .cloned())
     }
 }