feat: add slot lookup and write confirmations

[axelpaul]

Summary

Adds delivery and pickup availability lookup to the CLI, and makes all existing account-changing commands require an explicit confirmation flag.

New read-only commands

• kronan addresses — list saved delivery addresses (the default is identified in the human-readable output).
• kronan slots / kronan slots delivery — list live delivery slots for the default address and print the earliest available window first.
• kronan slots --address-id N — query a specific saved address.
• kronan slots pickup — print the next available pickup slot per Krónan store.
• All three support --json for callers that need structured output.

Delivery availability is fetched through the authenticated public API using the saved address ID. Fully booked slots are filtered out; availabilityStatus: -1 is presented as available/unlimited capacity.

Confirmation gate for mutations

Existing commands that change the Krónan account now stop before making an API call unless --yes is supplied. This covers:

• cart add/set/update/remove/clear;
• product-list create/delete/add/remove/clear;
• shopping-note add/update/remove/toggle/clear;
• purchase-stat ignore/unignore; and
• order-line delete, quantity reduction, and substitution changes.

Example: kronan cart add 02500188 2 --yes.

Cart --dry-run operations remain non-mutating and do not need confirmation.

Verification

• bun run lint
• bun run typecheck
• bun test — 27 passing tests
• Live authenticated smoke tests for delivery and pickup slot lookup