feat(web): fold Events/Agent/Audit into EntityDetail; tag agent_activity with entity_id

Events, Agent, and Audit were standalone read-only pages that never
cross-referenced the entity they related to. Fold them into EntityDetail
as entity-scoped cards (Agent activity, Audit trail) alongside the
existing Signals/Executions/Knowledge cards, and give the Signals card
real Ack/Mute/Resolve actions. Signals stays a standalone page since
it's the only one with cross-entity triage value (badge count, actions).

Also fixes the underlying reason those new cards would've stayed empty:
agent_activity rows were never tagged with entity_id at insert time
(cmd/nomos/store.go, internal/mcp/server.go), even though the column
and the API filter both support it. Added a best-effort resolver that
checks common tool-arg keys (target, entity_slug, slug, ...) against
the entities table.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

cmd/nomos/agent.go

@@ -442,7 +442,7 @@ func (a *agent) chatWith(ctx context.Context, sessionID, message, systemInject s
 			inputStr := string(inputJSON)
 
 			if callErr != nil {
-				a.store.logActivity(ctx, a.agentID, sessionID, tc.Function.Name, inputStr, callErr.Error(), elapsed, false, correlationID)
+				a.store.logActivity(ctx, a.agentID, sessionID, tc.Function.Name, args, inputStr, callErr.Error(), elapsed, false, correlationID)
 
 				emit(agentEvent{
 					Type:      "tool_result",
@@ -456,7 +456,7 @@ func (a *agent) chatWith(ctx context.Context, sessionID, message, systemInject s
 			}
 
 			resultJSON, _ := json.Marshal(result)
-			a.store.logActivity(ctx, a.agentID, sessionID, tc.Function.Name, inputStr, string(resultJSON), elapsed, true, correlationID)
+			a.store.logActivity(ctx, a.agentID, sessionID, tc.Function.Name, args, inputStr, string(resultJSON), elapsed, true, correlationID)
 
 			// Link any execution this tool queued/started back to this
 			// session, so the auto-continuation worker can feed its result