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>

frontend/src/domain/index.ts

@@ -313,6 +313,65 @@ export interface MemoryIndexEntry {
 /** A resolved `[[wikilink]]` target — the slug of another note. */
 export type MemoryLink = string;
 
+// ---------------------------------------------------------------------------
+// Embedder (L14 / lot C2) — mirror of the backend `EmbedderProfileDto` and
+// `EmbedderEnginesDto`. Drives the memory/embedder settings panel. Identity of
+// a profile is its `id`; changing the active embedder takes effect at the next
+// app start (the UI says so explicitly).
+// ---------------------------------------------------------------------------
+
+/**
+ * Embedding strategy of an embedder profile (mirror of the backend `strategy`).
+ * `none` ⇒ no vector tier (naïve recall); the other strategies select where the
+ * embeddings come from.
+ */
+export type EmbedderStrategy = "localOnnx" | "localServer" | "api" | "none";
+
+/**
+ * A declarative embedder profile (mirror of the backend `EmbedderProfile` DTO,
+ * camelCase wire format). Transparent by design: secrets are never stored here —
+ * `apiKeyEnv` is the *name* of an environment variable, never the key itself.
+ */
+export interface EmbedderProfile {
+  id: string;
+  name: string;
+  strategy: EmbedderStrategy;
+  /** Model id/name (ONNX model, server/api model). Omitted for `none`. */
+  model?: string;
+  /** Server/API endpoint URL. Omitted for `localOnnx` / `none`. */
+  endpoint?: string;
+  /** Name of the env var holding the API key (api strategy). Never the key. */
+  apiKeyEnv?: string;
+  /** Embedding vector dimension. */
+  dimension: number;
+}
+
+/**
+ * A recommended local ONNX engine (mirror of the backend `recommendedOnnx`
+ * entry). `e5-small` is the curated default (`recommended: true`).
+ */
+export interface RecommendedOnnxEngine {
+  id: string;
+  displayName: string;
+  dimension: number;
+  approxSizeMb: number;
+  recommended: boolean;
+}
+
+/**
+ * Capabilities/availability snapshot of the embedder engines on this build
+ * (mirror of the backend `describe_embedder_engines`). The `vector*Enabled`
+ * flags reflect Cargo feature flags compiled into the build: a strategy whose
+ * flag is `false` is shown disabled ("not available in this build").
+ */
+export interface EmbedderEngines {
+  recommendedOnnx: RecommendedOnnxEngine[];
+  ollamaDetected: boolean;
+  onnxCachedModels: string[];
+  vectorHttpEnabled: boolean;
+  vectorOnnxEnabled: boolean;
+}
+
 // ---------------------------------------------------------------------------
 // Templates (L7) — mirror of the domain `Template` / `AgentDrift`.
 // ---------------------------------------------------------------------------