fix(jtk): multi-checkbox custom fields only set last value

[rianjs]

Problem

When updating a multi-checkbox custom field (com.atlassian.jira.plugin.system.customfieldtypes:multicheckboxes) via jtk issue update, only a single value can be set. There's no syntax to set multiple values at once.

Attempt 1 — multiple --field flags with the same key:

jtk issue update ON-483 --field "customfield_10154=CheckSync" --field "customfield_10154=MoniCore" --field "customfield_10154=Monit Accounting"
# Result: only "Monit Accounting" is set (last value wins)

Attempt 2 — comma-separated values:

jtk issue update ON-483 --field 'customfield_10154=CheckSync,MoniCore,Monit Accounting'
# Result: bad request: Option value 'CheckSync,MoniCore,Monit Accounting' is not valid

Attempt 3 — array syntax:

jtk issue update ON-483 --field 'customfield_10154=[CheckSync,MoniCore,Monit Accounting]'
# Result: bad request: Option value '[CheckSync,MoniCore,Monit Accounting]' is not valid

Workaround

Direct REST API call works:

curl -X PUT "https://instance.atlassian.net/rest/api/3/issue/ON-483" \
  -u "user@example.com:$JIRA_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"fields":{"customfield_10154":[{"value":"CheckSync"},{"value":"MoniCore"},{"value":"Monit Accounting"}]}}'

Root Cause

The --field flag appears to parse values as a single string and construct a single-element array [{"value": "..."}] for select/checkbox fields. Duplicate --field keys overwrite rather than accumulate.

Proposed Solution

Support a delimiter syntax (e.g., pipe or semicolon) for multi-value fields:

jtk issue update ON-483 --field 'customfield_10154=CheckSync|MoniCore|Monit Accounting'

Or support repeated --field flags accumulating values for the same key rather than overwriting.

Version

jtk v0.3.0