feat(memory): config embedders (LOT C2) + suggestion contextuelle (LOT C3) + contexte projet partagé

- LOT C2 (§14.5.3) : use cases de configuration des embedders déclaratifs
  (List/Save/Delete + DescribeEmbedderEngines : modèles ONNX recommandés,
  environnement local détecté, stratégies compilées). UI EmbedderSettings.
- LOT C3 (§14.5.5) : suggestion contextuelle best-effort à l'activation quand la
  mémoire dépasse le budget de recall sans embedder configuré (event
  EmbedderSuggested, anti-spam 1×/session, « ne plus demander »).
- Contexte projet partagé .ideai/CONTEXT.md (model-agnostic) injecté à tous les
  agents/profils au lancement, avant la persona. UI ProjectContextPanel.

Tests : backend workspace vert (0 échec) ; frontend 306/306.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/infrastructure/tests/memory_recall.rs

@@ -22,7 +22,9 @@ use std::sync::{Arc, Mutex};
 use async_trait::async_trait;
 
 use domain::markdown::MarkdownDoc;
-use domain::memory::{Memory, MemoryFrontmatter, MemoryIndexEntry, MemoryLink, MemorySlug, MemoryType};
+use domain::memory::{
+    Memory, MemoryFrontmatter, MemoryIndexEntry, MemoryLink, MemorySlug, MemoryType,
+};
 use domain::ports::{
     DirEntry, FileSystem, FsError, MemoryError, MemoryQuery, MemoryRecall, MemoryStore, RemotePath,
 };
@@ -114,7 +116,10 @@ fn query(budget: usize) -> MemoryQuery {
 }
 
 fn slugs(entries: &[MemoryIndexEntry]) -> Vec<String> {
-    entries.iter().map(|e| e.slug.as_str().to_string()).collect()
+    entries
+        .iter()
+        .map(|e| e.slug.as_str().to_string())
+        .collect()
 }
 
 // ---------------------------------------------------------------------------
@@ -161,10 +166,7 @@ impl MemoryStore for CountingStore {
     async fn delete(&self, _root: &ProjectPath, _slug: &MemorySlug) -> Result<(), MemoryError> {
         panic!("recall must not call delete")
     }
-    async fn read_index(
-        &self,
-        _root: &ProjectPath,
-    ) -> Result<Vec<MemoryIndexEntry>, MemoryError> {
+    async fn read_index(&self, _root: &ProjectPath) -> Result<Vec<MemoryIndexEntry>, MemoryError> {
         self.read_index_calls.fetch_add(1, Ordering::SeqCst);
         Ok(Vec::new())
     }
@@ -224,17 +226,27 @@ async fn ample_budget_returns_all_entries_in_index_order() {
 
 #[tokio::test]
 async fn intermediate_budget_truncates_at_exact_boundary() {
-    let notes = [note("aaaa", "bbbb"), note("cccc", "dddd"), note("eeee", "ffff")];
+    let notes = [
+        note("aaaa", "bbbb"),
+        note("cccc", "dddd"),
+        note("eeee", "ffff"),
+    ];
     let recall = recall_over(&notes).await;
 
     // Budget 1 < 2 ⇒ first entry already exceeds ⇒ none.
     assert!(recall.recall(&root(), &query(1)).await.unwrap().is_empty());
 
     // Budget 2 == cost(1) ⇒ exactly the first entry; second (would reach 4) dropped.
-    assert_eq!(slugs(&recall.recall(&root(), &query(2)).await.unwrap()), vec!["aaaa"]);
+    assert_eq!(
+        slugs(&recall.recall(&root(), &query(2)).await.unwrap()),
+        vec!["aaaa"]
+    );
 
     // Budget 3 < 4 ⇒ still only the first.
-    assert_eq!(slugs(&recall.recall(&root(), &query(3)).await.unwrap()), vec!["aaaa"]);
+    assert_eq!(
+        slugs(&recall.recall(&root(), &query(3)).await.unwrap()),
+        vec!["aaaa"]
+    );
 
     // Budget 4 == cost(1)+cost(2) ⇒ first two; third (would reach 6) dropped.
     assert_eq!(
@@ -266,9 +278,15 @@ async fn entry_cost_rounds_up_via_ceil() {
     let recall = recall_over(&[note("ab", "c"), note("de", "fgh")]).await;
 
     // Budget 1 covers only the 1-token first entry; the 2-token second is dropped.
-    assert_eq!(slugs(&recall.recall(&root(), &query(1)).await.unwrap()), vec!["ab"]);
+    assert_eq!(
+        slugs(&recall.recall(&root(), &query(1)).await.unwrap()),
+        vec!["ab"]
+    );
     // Budget 2 still cannot fit the second on top of the first (1 + 2 = 3 > 2).
-    assert_eq!(slugs(&recall.recall(&root(), &query(2)).await.unwrap()), vec!["ab"]);
+    assert_eq!(
+        slugs(&recall.recall(&root(), &query(2)).await.unwrap()),
+        vec!["ab"]
+    );
     // Budget 3 fits both (1 + 2 == 3).
     assert_eq!(
         slugs(&recall.recall(&root(), &query(3)).await.unwrap()),