Stop traversal past scalar JSON values

[memotype]

Summary

• stop path traversal when the selected JSON value is a scalar, returning status 1 instead of scanning into a sibling
• cover string, number, boolean, null, array-element, nested, and multi-term scalar traversal cases
• cover unsupported empty query terms, left-to-right failure precedence, no-query extraction, and empty-string values
• regenerate all compact forms while preserving their existing physical line counts

Verification

• make verify
• forced regeneration produced byte-identical generated outputs
• generated totals remain 2 lines for bj-1line.sh, 11 for bj-80-col.sh, and 10 for bj-90-col.sh

Closes #21
Closes #29