feat(memory): add shared foundation types, Zod schemas, and roundtrip tests (plan 21 F1)

- src/lib/memory/embedding/types.ts — EmbeddingSource, EmbeddingProviderListing, EmbeddingResolution, EmbeddingResult, EmbeddingError (verbatim §3.1)
- src/shared/schemas/memory.ts — 7 Zod schemas (MemorySettingsExtended, MemoryUpdatePut, RetrievePreview, MemoryReindex, MemorySummarize, EmbeddingProviderListing, MemoryEngineStatus, RetrievePreviewResult) + z.infer types (verbatim §3.2)
- src/shared/schemas/qdrant.ts — 4 Zod schemas (QdrantSettings, QdrantSettingsUpdate, QdrantSearch, QdrantHealthResult) + z.infer types (verbatim §3.3)
- tests/unit/memory-schemas-roundtrip.test.ts — 34 assertions (≥22 required); all pass

src/lib/memory/embedding/types.ts

@@ -0,0 +1,40 @@
+export type EmbeddingSource = "remote" | "static" | "transformers" | "auto";
+
+export interface EmbeddingProviderListing {
+  provider: string; // e.g. "openai"
+  hasKey: boolean;
+  models: Array<{
+    id: string; // formato `provider/model`, e.g. "openai/text-embedding-3-small"
+    name: string;
+    dimensions: number | null;
+  }>;
+}
+
+export interface EmbeddingResolution {
+  /** Fonte ativa após resolveEmbeddingSource(settings). null = nenhuma disponível → degrada p/ FTS5. */
+  source: "remote" | "static" | "transformers" | null;
+  /** Modelo ativo (formato provider/model para remote, "potion-base-8M" para static, "Xenova/all-MiniLM-L6-v2" para transformers). */
+  model: string | null;
+  /** Dimensão do vetor produzido. null antes da 1ª chamada (lazy probe). */
+  dimensions: number | null;
+  /** Assinatura única usada como chave do vectorStore para detectar troca de modelo. */
+  signature: string; // ${source}:${model}:${dim}
+  /** Motivo da escolha (UI exibe no Engine status). */
+  reason: string; // e.g. "provider openai com key configurada"
+}
+
+export interface EmbeddingResult {
+  vector: Float32Array;
+  source: "remote" | "static" | "transformers";
+  model: string;
+  dimensions: number;
+  latencyMs: number;
+  cached: boolean;
+}
+
+export interface EmbeddingError {
+  source: "remote" | "static" | "transformers";
+  model: string | null;
+  reason: "no_key" | "model_load_failed" | "request_failed" | "rate_limited" | "timeout" | "unknown";
+  message: string; // ALWAYS via sanitizeErrorMessage()
+}