CLI: Auto-split comma-separated values in put command

[arcaputo3]

Summary

When using put with a range and comma-separated values, the CLI currently treats the entire string as a single text value:

xl -f file.xlsx -s Sheet1 -o out.xlsx put A1:A5 1,2,3,4,5
# Current: All 5 cells get text "1,2,3,4,5"
# Expected: A1=1, A2=2, A3=3, A4=4, A5=5

Proposed Behavior

When the number of comma-separated values matches the number of cells in the range, distribute values across cells with smart type detection.

Considerations

1. Ambiguity: What if someone wants literal text "1,2,3,4,5"?

   • Option A: Add --no-split flag to preserve literal behavior
   • Option B: Only split when count matches exactly, otherwise treat as text
   • Option C: Require quotes for literal text: put A1 '"1,2,3,4,5"'

2. Smart detection: Apply same auto-detection as batch JSON (numbers, dates, currency, percent)

3. Edge cases:

   • Quoted values with commas: "Hello, World",Foo,Bar
   • Trailing/leading whitespace handling
   • Empty values: 1,,3 (should become 1, empty, 3?)

Workaround

Use batch JSON syntax which already supports this:

echo '[{"op":"put","ref":"A1","value":1},{"op":"put","ref":"A2","value":2}]' | xl -f file.xlsx -s Sheet1 -o out.xlsx batch -

Priority

Low - ergonomics improvement, not a blocker.