bd create: support --description=- for stdin input

Allows descriptions with apostrophes and other shell-problematic
characters by reading from stdin. Works with both --description=-
and --body=- (the GitHub CLI-style alias).

Example: echo "It's working" | bd create --title "Test" --description=-

Also fixes pre-existing duplicate pinned column/variable declarations.

Fixes beads-iwi

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

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

internal/storage/sqlite/issues.go

@@ -36,11 +36,6 @@ func insertIssue(ctx context.Context, conn *sql.Conn, issue *types.Issue) error
 		pinned = 1
 	}
 
-	pinned := 0
-	if issue.Pinned {
-		pinned = 1
-	}
-
 	_, err := conn.ExecContext(ctx, `
 		INSERT OR IGNORE INTO issues (
 			id, content_hash, title, description, design, acceptance_criteria, notes,
@@ -100,11 +95,6 @@ func insertIssues(ctx context.Context, conn *sql.Conn, issues []*types.Issue) er
 			pinned = 1
 		}
 
-		pinned := 0
-		if issue.Pinned {
-			pinned = 1
-		}
-
 		_, err = stmt.ExecContext(ctx,
 			issue.ID, issue.ContentHash, issue.Title, issue.Description, issue.Design,
 			issue.AcceptanceCriteria, issue.Notes, issue.Status,