fix: migration 022 fails with SQL syntax error on v0.30.3 upgrade

db.Exec was being passed %s format specifiers directly in the SQL
string, but db.Exec does not do printf-style formatting - it uses the
variadic args as SQL parameter bindings. This caused the literal %s
to be sent to SQLite, which failed with near percent: syntax error.

Fixed by using fmt.Sprintf to interpolate the column expressions into
the SQL string before passing to db.Exec.

Added regression test that creates an old-schema database with edge
columns (replies_to, relates_to, duplicate_of, superseded_by) and
verifies migration 022 completes successfully.

Fixes #809

Generated with Claude Code

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

internal/storage/sqlite/migrations/022_drop_edge_columns.go

@@ -183,7 +183,9 @@ func MigrateDropEdgeColumns(db *sql.DB) error {
 	}
 
 	// Copy data from old table to new table (excluding deprecated columns)
-	_, err = db.Exec(`
+	// NOTE: We use fmt.Sprintf here (not db.Exec parameters) because we're interpolating
+	// column names/expressions, not values. db.Exec parameters only work for VALUES.
+	copySQL := fmt.Sprintf(`
 		INSERT INTO issues_new (
 			id, content_hash, title, description, design, acceptance_criteria,
 			notes, status, priority, issue_type, assignee, estimated_minutes,
@@ -203,6 +205,7 @@ func MigrateDropEdgeColumns(db *sql.DB) error {
 			COALESCE(close_reason, '')
 		FROM issues
 	`, pinnedExpr, isTemplateExpr, awaitTypeExpr, awaitIDExpr, timeoutNsExpr, waitersExpr)
+	_, err = db.Exec(copySQL)
 	if err != nil {
 		return fmt.Errorf("failed to copy issues data: %w", err)
 	}