Marketplace: warn on imported global plugins; tidy import follow-ups

- The import preview counts global plugin installs and warns on them:
  a plugin can bring hooks and MCP servers into every container and an
  imported install skips the confirm step, like a hook.
- Item keys, hosts and branches in errors are quoted with {:?} and
  capped, since they can come from an import file.
- After an import, caches and snapshots of marketplaces the import
  dropped are removed (under the repo lock) and pins are refreshed for
  the imported installs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/src-tauri/src/commands/marketplace_commands.rs

@@ -62,6 +62,19 @@ pub(crate) mod ops {
         }
     }
 
+    /// An unvalidated value as it may appear in an error: quoted and escaped
+    /// (`{:?}`) and capped at 60 characters, since it can come from an
+    /// import file rather than from what the person just typed.
+    pub fn shown(value: &str) -> String {
+        const MAX: usize = 60;
+        if value.chars().count() > MAX {
+            let head: String = value.chars().take(MAX).collect();
+            format!("{:?}…", head)
+        } else {
+            format!("{:?}", value)
+        }
+    }
+
     pub fn validate_label(label: &str) -> Result<String, String> {
         let label = label.trim();
         if label.is_empty() {
@@ -86,7 +99,7 @@ pub(crate) mod ops {
         if git::valid_branch(&b) {
             Ok(Some(b))
         } else {
-            Err(format!("{b:?} is not a valid branch name."))
+            Err(format!("{} is not a valid branch name.", shown(&b)))
         }
     }
 
@@ -101,7 +114,7 @@ pub(crate) mod ops {
         if auth::valid_host(&host) && !host.starts_with('.') && !host.starts_with(':') && port_ok {
             Ok(host)
         } else {
-            Err(format!("{host:?} is not a valid host name."))
+            Err(format!("{} is not a valid host name.", shown(&host)))
         }
     }
 
@@ -294,7 +307,10 @@ fn validate_item(item: &MarketplaceItemRef) -> Result<(), String> {
     if is_valid_item_key(&item.key) {
         Ok(())
     } else {
-        Err(format!("\"{}\" is not a valid item name.", item.key))
+        Err(format!(
+            "{} is not a valid item name.",
+            ops::shown(&item.key)
+        ))
     }
 }
 
@@ -382,6 +398,17 @@ pub(crate) fn validate_imported_marketplace_state(
     Ok(())
 }
 
+/// Marketplaces configured in `before` that `after` no longer has: an import
+/// that drops them leaves their caches and snapshots to be removed.
+pub(crate) fn dropped_marketplace_ids(before: &AppSettings, after: &AppSettings) -> Vec<String> {
+    before
+        .marketplaces
+        .iter()
+        .filter(|m| !after.marketplaces.iter().any(|a| a.id == m.id))
+        .map(|m| m.id.clone())
+        .collect()
+}
+
 /// The in-memory snapshot, else the cached one (which is then remembered).
 fn snapshot_or_cached(mgr: &MarketplaceManager, m: &Marketplace) -> MarketplaceSnapshot {
     if let Some(s) = mgr.snapshot(&m.id) {
@@ -406,7 +433,7 @@ async fn snapshot_blocking(
 /// Make each cache's pin refs exactly the commits installs reference, so a
 /// pinned version can never be garbage-collected away. Under the repo lock
 /// (pre-flight F11): a concurrent fetch writes refs in the same repos.
-async fn refresh_pins(state: &AppState) {
+pub(crate) async fn refresh_pins(state: &AppState) {
     let settings = state.settings_store.get();
     let pins = mk::pins_by_marketplace(&settings, &state.projects_store.list());
     let root = state.marketplace.data_root().to_path_buf();
@@ -432,7 +459,7 @@ async fn refresh_pins(state: &AppState) {
 }
 
 /// Forget a marketplace's snapshot and delete its cache, under the repo lock.
-async fn remove_cache(state: &AppState, marketplace_id: &str) {
+pub(crate) async fn remove_cache(state: &AppState, marketplace_id: &str) {
     state.marketplace.remove_snapshot(marketplace_id);
     let path = git::cache_path(state.marketplace.data_root(), marketplace_id);
     let _repo_guard = state.marketplace.repo_lock().lock().await;
@@ -1144,4 +1171,38 @@ mod tests {
         s.marketplaces.clear();
         validate_imported_marketplace_state(&mut s, &tokens()).unwrap();
     }
+
+    #[test]
+    fn an_invalid_item_key_is_quoted_and_capped_in_the_error() {
+        use crate::models::marketplace::MarketplaceItemRef;
+        let item = |key: String| MarketplaceItemRef {
+            marketplace_id: MARKET.into(),
+            kind: ItemKind::Agent,
+            key,
+        };
+        let e = validate_item(&item("bad\nkey".into())).unwrap_err();
+        assert!(!e.contains('\n'), "raw control character in {e:?}");
+        assert!(e.contains("\"bad\\nkey\""), "{e}");
+        let e = validate_item(&item(format!("{}/", "x".repeat(500)))).unwrap_err();
+        assert!(
+            e.chars().count() < 150,
+            "not capped: {} chars",
+            e.chars().count()
+        );
+    }
+
+    #[test]
+    fn marketplaces_an_import_drops_are_the_ones_whose_caches_go() {
+        let mut before = imported();
+        let mut kept = before.marketplaces[0].clone();
+        kept.id = "kept-1".into();
+        before.marketplaces.push(kept.clone());
+        let mut after = AppSettings::default();
+        after.marketplaces.push(kept);
+        assert_eq!(
+            dropped_marketplace_ids(&before, &after),
+            vec![MARKET.to_string()]
+        );
+        assert!(dropped_marketplace_ids(&after, &before).is_empty());
+    }
 }

app/src-tauri/src/commands/settings_export_commands.rs

@@ -441,6 +441,13 @@ pub async fn apply_settings_import(
         ) = imported_marketplace;
         state.settings_store.update(s)?
     };
+    // Caches of marketplaces the import dropped are dead weight now, and
+    // the pins must match the imported installs.
+    use crate::commands::marketplace_commands as mc;
+    for id in mc::dropped_marketplace_ids(&current, &saved) {
+        mc::remove_cache(&state, &id).await;
+    }
+    mc::refresh_pins(&state).await;
 
     // `reconcile_gateway` (inside `update_settings`) only reacts to a changed
     // *shape* — port, provider, base URL, models — because that's what's