feat(cli): reach the four inbox routes the generic factory cannot

[yvoolab]

The public v2 schema declares five inbox routes. The CLI reaches one of them.

GET /public/v2/inbox/                            -> {transactions_count, records_count}
GET /public/v2/inbox/transactions/               -> {items, count}
GET /public/v2/inbox/records/                    -> {items, count}
GET /public/v2/inbox/transactions/{record_id}/   -> requires query transaction_type
GET /public/v2/inbox/records/{record_id}/        -> requires query record_type

main.py registers inbox against path inbox, so dualentry inbox list calls the
summary route. That response carries no items/count, so format_output sends it to
_print_detail and the command prints a two-row table of counts. With --all, paginate
finds no items key, stops on the first page and the command prints "No results."

The two detail routes cannot be served by the generic factory at all: both take a required
type discriminator as a query parameter, and the factory's get sends only the path. #24
notes this in its description.

What this adds

New commands/inbox.py, wired as two sub-groups under the existing inbox group
(hand-written module, following the commands/accounts.py precedent):

dualentry inbox transactions list [--transaction-type ... --status ... --company ...
                                   --customer ... --search --start-date --end-date
                                   --min-amount --max-amount --limit --offset --all]
dualentry inbox transactions get <record_id> --transaction-type <type>
dualentry inbox records list      [--record-type ... --status ... --search --limit --offset --all]
dualentry inbox records get      <record_id> --record-type <type>

Filter flags are the ones the two list routes declare in the schema, minus the by-id
lookups (record_id, transaction_id); repeatable ones are sent as repeated query
params. --status maps to approval_status, which is what these routes call it.

Two smaller things ride along because the new commands are the first to need them:

• _resume_all_command now repeats a flag for a list-valued filter instead of printing
  the Python list, so the --all resume hint stays copy-pasteable.
• get prints "This record is not in the inbox." instead of an empty table when the API
  answers with an empty object, which the schema documents as the not-in-inbox case.
  --format json still prints {} so scripts are unaffected.

Happy to drop either of those into a separate PR if you would rather keep this to the four
commands.

Not touched

• inbox get stays unregistered — tests/test_stale_commands.py locks that, and the lock
  still passes (sub-groups land in registered_groups, not registered_commands).
• inbox list still calls the summary route, unchanged.
• No dependency changes, so uv.lock is untouched.

Verification

uv run pytest                 ->  252 passed, 125 skipped   (baseline 242 passed)
uv run ruff check .           ->  All checks passed
uv run ruff format --check .  ->  31 files already formatted

Ten new tests in tests/test_commands.py::TestInboxCommands, mock-based like the rest of
that file: route and params for each of the four commands, the required discriminator
(exit code 2 without it), the empty-object path in both output formats, the resume-hint
repeat, and a regression guard that inbox list still hits /inbox/.

One limitation worth stating plainly: I have no credentials for the API, so every test is
mocked and none of this has been run against a live inbox response.

[Warkanlock]

Thanks for your contributions!

[Warkanlock]

Reproducible proof required

This PR description has no reproducible-proof artifact — no image, screenshot, screen recording, curl example, or documented reproduction/verification steps.

Please edit the PR description to include evidence the change works, then mark the PR ready for review.

Recommended for this PR: reproduction steps plus the command output (test run, curl, logs, or a screenshot) proving the change works.

Any of these count as proof:

• Screenshot or before/after image of the affected UI
• Short screen recording (Loom / uploaded video)
• curl request + response for API changes
• Copy-pasted test output or logs under a Test plan / Steps to reproduce heading

Moved to draft until proof is added.