fix: make library suggestions available in module files (#11373)

This PR makes the library suggestions extension state available when
importing from `module` files.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

src/Lean/LibrarySuggestions.lean

@@ -6,8 +6,8 @@ Authors: Kim Morrison
 module
 
 prelude
-import Lean.LibrarySuggestions.Basic
+public import Lean.LibrarySuggestions.Basic
 import Lean.LibrarySuggestions.SymbolFrequency
 import Lean.LibrarySuggestions.MePo
-import Lean.LibrarySuggestions.SineQuaNon
-import Lean.LibrarySuggestions.Default
+public import Lean.LibrarySuggestions.SineQuaNon
+public import Lean.LibrarySuggestions.Default

tests/lean/run/library_suggestions_persistent.lean

@@ -1,6 +1,5 @@
 import Lean.LibrarySuggestions
 import Lean.Meta.Basic
-import Std.Data.ExtHashMap
 
 /-!
 # Test that library suggestions persist across file boundaries

tests/lean/run/library_suggestions_persistent_module.lean

@@ -0,0 +1,36 @@
+module
+import Lean
+
+/-!
+# Test that library suggestions persist across file boundaries
+
+This test verifies that the default library suggestion engine set in
+`Lean.LibrarySuggestions.Default` is correctly persisted when imported via `Lean.LibrarySuggestions`.
+
+We do NOT call `set_library_suggestions` in this file - the selector should
+already be set from importing Lean.LibrarySuggestions (which imports Default).
+-/
+
+/--
+info: ✓ Selector found in imported state: (Term.open
+ "open"
+ (Command.openSimple [`Lean.LibrarySuggestions])
+ "in"
+ (Term.app `sineQuaNonSelector.filterGrindAnnotated.intersperse [`currentFile]))
+---
+info:   ✓ Successfully retrieved selector using getSelector!
+-/
+#guard_msgs in
+open Lean Lean.LibrarySuggestions in
+run_cmd do
+  let stx? := librarySuggestionsExt.getState (← getEnv)
+  match stx? with
+  | none => Lean.logInfo "❌ No selector found in imported state!"
+  | some stx =>
+    Lean.logInfo s!"✓ Selector found in imported state: {stx}"
+    -- Try to retrieve the selector using getSelector
+    Elab.Command.liftTermElabM do
+      let selector? ← getSelector
+      match selector? with
+      | none => Lean.logInfo "  ❌ getSelector returned none"
+      | some _ => Lean.logInfo "  ✓ Successfully retrieved selector using getSelector!"