fix(cli): parse JSON --item strings in add-checklist CLI command

[aaight]

Summary

• Root cause: cascade-tools pm add-checklist was passing --item flag values as raw strings to addChecklist(). When the Claude Code agent serialised checklist items as JSON (--item '{"name":"...","description":"..."}'), the entire JSON blob became the JIRA subtask title.
• Fix: Added a parseItem() helper in src/cli/pm/add-checklist.ts that tries JSON.parse() on each --item string and, if the result is an object with a name string property, returns a ChecklistItemInput object. All other values (invalid JSON, JSON without name, plain strings) pass through unchanged.
• Scope: Only affects the Claude Code backend path (CLI-based tool invocation). The llmist backend uses the gadget directly and is unaffected.

Card: https://trello.com/c/699f3cbe3124db0241b61aef

Test plan

• parseItem unit tests: plain strings, JSON with name+description, JSON with name only, invalid JSON, JSON without name, JSON arrays, JSON primitives, non-string description
• Integration tests via addChecklist(): plain strings, JSON objects, mixed items, unparseable JSON, JSON without name
• All 17 new tests pass
• Existing addChecklist gadget tests unaffected
• Lint and typecheck pass

🤖 Generated with Claude Code

[aaight]

⚙️ On it — checking the CI failures for PR 554

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Progress: [██░░░░░░░░] 20% (iteration 14/70)

🔧 CI Fix Update (1 min)

I've identified that the CI failure is not due to the PR's code changes but a transient npm ci error (403 from npm registry). I've re-run the failed CI job and confirmed the working tree is clean. I'm now locally verifying that all CI steps pass to ensure the fix is complete.

_{Last updated: iteration 14 · respond-to-ci}

[aaight]

⚙️ On it — checking the CI failures for PR 554

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Progress: [██░░░░░░░░] 17% (iteration 12/70)

🔧 CI Fix Update (1 min)

I've started by investigating the CI failure for work item 699f3cbe3124db0241b61aef. I've identified that the failure is due to a transient npm ci issue, specifically a 403 Forbidden error from the npm registry for the adm-zip package, which is unrelated to the code changes in the PR. I'm currently verifying other CI checks to ensure there are no other underlying issues.

_{Last updated: iteration 12 · respond-to-ci}

[nhopeatall]

✨ On it — checking the CLI checklist JSON parsing fix

[nhopeatall]

LGTM — clean, well-scoped fix. The parseItem() helper correctly parses JSON --item strings into ChecklistItemInput objects while preserving backward compatibility for plain strings. The type-narrowing logic is sound (null check, typeof === 'object', \!Array.isArray, typeof name === 'string'), and the fallback on JSON.parse failure is appropriate. Test coverage is thorough with both unit and integration tests. All CI checks pass.