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/application/src/memory/mod.rs

@@ -16,8 +16,8 @@ mod usecases;
 
 pub use usecases::{
     CreateMemory, CreateMemoryInput, CreateMemoryOutput, DeleteMemory, DeleteMemoryInput,
-    GetMemory, GetMemoryInput, GetMemoryOutput, ListMemories, ListMemoriesInput, ListMemoriesOutput,
-    ReadMemoryIndex, ReadMemoryIndexInput, ReadMemoryIndexOutput, RecallMemory, RecallMemoryInput,
-    RecallMemoryOutput, ResolveMemoryLinks, ResolveMemoryLinksInput, ResolveMemoryLinksOutput,
-    UpdateMemory, UpdateMemoryInput, UpdateMemoryOutput,
+    GetMemory, GetMemoryInput, GetMemoryOutput, ListMemories, ListMemoriesInput,
+    ListMemoriesOutput, ReadMemoryIndex, ReadMemoryIndexInput, ReadMemoryIndexOutput, RecallMemory,
+    RecallMemoryInput, RecallMemoryOutput, ResolveMemoryLinks, ResolveMemoryLinksInput,
+    ResolveMemoryLinksOutput, UpdateMemory, UpdateMemoryInput, UpdateMemoryOutput,
 };