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/app-tauri/tests/dto_agents.rs

@@ -11,8 +11,8 @@ use application::AppError;
 use application::{
     CreateAgentOutput, InspectConversationOutput, LaunchAgentOutput, ListAgentsOutput,
 };
-use domain::ports::ConversationDetails;
 use domain::ids::{AgentId, NodeId, ProfileId, SessionId};
+use domain::ports::ConversationDetails;
 use domain::terminal::{PtySize, SessionKind, SessionStatus, TerminalSession};
 use domain::{Agent, AgentOrigin, ProjectPath};
 use serde_json::json;
@@ -44,7 +44,10 @@ fn agent_dto_serialises_camelcase() {
     assert_eq!(v["id"], agent.id.to_string());
     assert_eq!(v["name"], "My Agent");
     assert_eq!(v["contextPath"], "agents/my-agent.md", "camelCase key");
-    assert_eq!(v["profileId"], ProfileId::from_uuid(Uuid::from_u128(2)).to_string());
+    assert_eq!(
+        v["profileId"],
+        ProfileId::from_uuid(Uuid::from_u128(2)).to_string()
+    );
     assert_eq!(v["synchronized"], false);
     // origin: tagged `{ "type": "scratch" }`
     assert_eq!(v["origin"]["type"], "scratch");
@@ -68,7 +71,9 @@ fn agent_list_dto_is_transparent_array() {
 #[test]
 fn create_agent_output_maps_to_agent_dto() {
     let agent = make_agent(5, 6);
-    let out = CreateAgentOutput { agent: agent.clone() };
+    let out = CreateAgentOutput {
+        agent: agent.clone(),
+    };
     let dto = AgentDto::from(out);
     assert_eq!(dto.0.id, agent.id);
 }
@@ -168,19 +173,25 @@ fn agent_already_running_error_code_is_stable() {
     // Option A: a stable code + a text message (the node is NOT enriched into the
     // ErrorDto — the frontend branches on the code alone).
     assert_eq!(dto.code, "AGENT_ALREADY_RUNNING");
-    assert!(dto.message.contains("already running"), "message: {}", dto.message);
+    assert!(
+        dto.message.contains("already running"),
+        "message: {}",
+        dto.message
+    );
 }
 
 #[test]
 fn live_agent_list_dto_serialises_camelcase_array() {
     let agent_a = AgentId::from_uuid(Uuid::from_u128(11));
     let node_a = NodeId::from_uuid(Uuid::from_u128(21));
-    let dto = LiveAgentListDto::from_pairs(vec![(agent_a, node_a)]);
+    let session_a = domain::SessionId::from_uuid(Uuid::from_u128(31));
+    let dto = LiveAgentListDto::from_pairs(vec![(agent_a, node_a, session_a)]);
     let v = serde_json::to_value(&dto).unwrap();
     let arr = v.as_array().expect("transparent array");
     assert_eq!(arr.len(), 1);
     assert_eq!(arr[0]["agentId"], agent_a.to_string());
     assert_eq!(arr[0]["nodeId"], node_a.to_string());
+    assert_eq!(arr[0]["sessionId"], session_a.to_string());
     // No snake_case leak.
     assert!(arr[0].get("agent_id").is_none());
     assert!(arr[0].get("node_id").is_none());
@@ -246,7 +257,10 @@ fn conversation_details_dto_omits_fields_when_none() {
     let v = serde_json::to_value(&dto).unwrap();
     // Both optional fields are omitted from the wire (absent, not null).
     assert!(v.get("lastTopic").is_none(), "absent topic ⇒ field omitted");
-    assert!(v.get("tokenCount").is_none(), "absent tokens ⇒ field omitted");
+    assert!(
+        v.get("tokenCount").is_none(),
+        "absent tokens ⇒ field omitted"
+    );
     assert_eq!(v, json!({}), "fully degraded ⇒ empty object");
 }