Layered product + team working memory (Slice 3)

Generalizes working memory to a scope: ITeamMemory becomes IWorkingMemory with a
MemoryScope (Team | Product); MemoryEntry's TeamId becomes ScopeType+ScopeId (data-
preserving rename migration). On approval, Governance writes the decision/correction
at PRODUCT scope when the team belongs to a product (resolved via IBoardStats), so it
is shared by every agent across the product's teams — else at team scope. The assembler
recalls product memory (shared) plus team memory (local), merged by relevance, under a
"# Shared memory" section.

This is the other half of product-centric agents: a decision approved on one team now
informs every agent on the product, not just that team.

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

src/Shared/TeamUp.SharedKernel/Ai/IWorkingMemory.cs

@@ -0,0 +1,40 @@
+namespace TeamUp.SharedKernel.Ai;
+
+public enum MemoryKind
+{
+    Decision,
+    Approval,
+    Correction,
+}
+
+/// <summary>The scope a memory belongs to: a single team (local, tactical) or a whole product (shared).</summary>
+public enum MemoryScope
+{
+    Team,
+    Product,
+}
+
+public sealed record MemoryHit(Guid Id, MemoryKind Kind, string Content, DateTimeOffset CreatedAtUtc);
+
+/// <summary>
+/// Working memory: written when a human approves (or corrects) agent work, read at prompt assembly
+/// via pgvector similarity. Scoped to a team (local context) or a product (shared by every agent
+/// across the product's teams). Implemented by the Memory module.
+/// </summary>
+public interface IWorkingMemory
+{
+    Task WriteAsync(
+        MemoryScope scope,
+        Guid scopeId,
+        MemoryKind kind,
+        string content,
+        Guid? sourceReviewItemId = null,
+        CancellationToken cancellationToken = default);
+
+    Task<IReadOnlyList<MemoryHit>> SearchAsync(
+        MemoryScope scope,
+        Guid scopeId,
+        string query,
+        int take = 3,
+        CancellationToken cancellationToken = default);
+}