feat: add type: event for operational state changes (bd-ecmd)

Adds support for event beads that capture operational state transitions
as immutable records. Events are a new issue type with fields:
- event_kind: namespaced category (patrol.muted, agent.started)
- actor: entity URI who caused the event
- target: entity URI or bead ID affected
- payload: event-specific JSON data

This enables:
- bd activity --follow showing events
- bd list --type=event --target=agent:deacon
- Full audit trail for operational state
- HOP-compatible transaction records

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Executed-By: beads/crew/dave
Rig: beads
Role: crew

internal/storage/sqlite/queries.go

@@ -281,6 +281,11 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 	var rig sql.NullString
 	// Molecule type field
 	var molType sql.NullString
+	// Event fields
+	var eventKind sql.NullString
+	var actor sql.NullString
+	var target sql.NullString
+	var payload sql.NullString
 
 	var contentHash sql.NullString
 	var compactedAtCommit sql.NullString
@@ -292,7 +297,8 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 		       deleted_at, deleted_by, delete_reason, original_type,
 		       sender, ephemeral, pinned, is_template,
 		       await_type, await_id, timeout_ns, waiters,
-		       hook_bead, role_bead, agent_state, last_activity, role_type, rig, mol_type
+		       hook_bead, role_bead, agent_state, last_activity, role_type, rig, mol_type,
+		       event_kind, actor, target, payload
 		FROM issues
 		WHERE id = ?
 	`, id).Scan(
@@ -305,6 +311,7 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 		&sender, &wisp, &pinned, &isTemplate,
 		&awaitType, &awaitID, &timeoutNs, &waiters,
 		&hookBead, &roleBead, &agentState, &lastActivity, &roleType, &rig, &molType,
+		&eventKind, &actor, &target, &payload,
 	)
 
 	if err == sql.ErrNoRows {
@@ -406,6 +413,19 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 	if molType.Valid {
 		issue.MolType = types.MolType(molType.String)
 	}
+	// Event fields
+	if eventKind.Valid {
+		issue.EventKind = eventKind.String
+	}
+	if actor.Valid {
+		issue.Actor = actor.String
+	}
+	if target.Valid {
+		issue.Target = target.String
+	}
+	if payload.Valid {
+		issue.Payload = payload.String
+	}
 
 	// Fetch labels for this issue
 	labels, err := s.GetLabels(ctx, issue.ID)