fix: migration 028 handles missing created_by column

The migration was using SELECT * which fails when migrating databases
that predate the created_by column (34 columns vs 35). Now explicitly
lists columns and provides empty default for created_by if missing.

Also fixes missed Wisp→Ephemeral rename in multirepo_test.go.

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

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

internal/storage/sqlite/multirepo_test.go

@@ -909,7 +909,7 @@ func TestUpsertPreservesGateFields(t *testing.T) {
 		Status:    types.StatusOpen,
 		Priority:  1,
 		IssueType: types.TypeGate,
-		Wisp:      true,
+		Ephemeral: true,
 		AwaitType: "gh:run",
 		AwaitID:   "123456789",
 		Timeout:   30 * 60 * 1000000000, // 30 minutes in nanoseconds