Phase 4C: CompanyInfo, Preferences, Attachable

[greerso]

Summary

Add three entity groups to close open bookkeeper questions and fix Stripe PDF links:

• CompanyInfo (get_company_info) — subscription plan tier (gates Class/Dept/PO/TimeActivity), fiscal year start month, multicurrency status, country
• Preferences (get_preferences) — accrual vs cash basis default, Class/Dept tracking on/off, POEnabled
• Attachable (create_attachable, get_attachable, search_attachables, delete_attachable) — upload Stripe invoice PDFs as real QBO file attachments linked to invoices, replacing freetext in PrivateNote

Motivation (from bookkeeper analysis, Jun 2026)

• Bookkeeper currently guesses at subscription plan, fiscal year start, and multicurrency status — CompanyInfo closes all three
• 12 invoices have Stripe invoice PDF URLs buried in PrivateNote; create_attachable moves them to QBO's document viewer as downloadable attachments
• Accrual/cash basis default unknown; Preferences closes this

[Soumiya-mohan]

Status update — 2 of the 3 entity groups are done on main, one remains:

• CompanyInfo — get_company_info present ✅
• Attachable — create_attachable, get_attachable, search_attachables, delete_attachable all present ✅. create_attachable was also enhanced (feat(create_attachable): add file_path and file_url sources with stre… #97) to upload by file_path/file_url (with path confinement + streaming) — directly supports the "move Stripe invoice PDFs out of PrivateNote into real QBO attachments" motivation here.
• Preferences — ❌ still missing as a user-facing tool. There's currently only an internal getPreferences call (added in fix(update-bill): preserve line ClassRef/TaxCodeRef via read-merge-write #86 for automated-sales-tax detection in update-bill); there's no get_preferences tool exposing accrual-vs-cash basis default, Class/Dept tracking flags, or POEnabled.

Leaving this open to track the remaining get_preferences read-only tool. It's a small addition — a tool wrapping the same getPreferences call already used internally, surfacing the accounting-method and tracking flags. Happy to take a PR, or we can pick it up.