Tasks: the bus keeps an outbox, and `status` reads it

The last spec artifact. Derived from design.md and testing-plan.md. Gate-less (issue-281): it advances on shape.

Execution DAG

Tasks

[x] 1 · Declare the path. Add StateLayout.channels_outbox (<root>/channels/undelivered.json) and its GeneratedPath entry in cli/the_loop/state.py, classified local with its reason; add the row, the tree line and the section to docs/cli/state.md. Requirements: R1.1. Test: testing-plan T8, T12.
[x] 2 · The outbox. Write cli/the_loop/channels/outbox.py — path_for, remember, entries, summary, the entry round trip, the lock, the cap and the backoff — per design.md § Components. Write cli/tests/test_channels_outbox.py first, red, then implement. Document channel.undelivered and channel.undelivered_dropped in eventlog.EVENT_TYPES. Requirements: R1.1, R1.2, R1.3, R1.4, R1.5, R1.6, R4.1. Test: testing-plan T1, T7, T8, T9.
[x] 3 · The drain. Add drain and start_drainer to the same module: the per-entry backoff, the per-cycle budget, removal on delivery, and the watcher-shaped thread. Document channel.delivered_late. Requirements: R2.1, R2.2, R2.3, R2.4, R2.5, R2.6. Test: testing-plan T2, T7, T9.
[x] 4 · The bus writes it. Add the three-guard call at the end of channels/bus.py's publish, and its test in cli/tests/test_bus.py and cli/tests/test_bus_integration.py. Requirements: R1.1, R1.2, R1.3, R1.6. Test: testing-plan T3.
[x] 5 · The daemons drain it. Start outbox.start_drainer beside channels_watcher.start_watcher in cli/the_loop/poller/daemon.py and cli/the_loop/webhook/daemon.py. Requirements: R2.1, R2.6. Test: testing-plan T4, T10.
[x] 6 · The status line. Add channelDelivery to lifecycle.status_all's report and undelivered_line beside environment_line; print it in commands/lifecycle_cmd.py's StatusCommand. Requirements: R3.1, R3.2, R3.3, R3.4, R3.5. Test: testing-plan T5.
[x] 7 · The session is told. In core/sessions.py's ask_session, add the no-channel-took-it note and the channels_posted field on the session.awaiting_input event; update the event's EVENT_TYPES description. Requirements: R4.2, R4.3, R4.4. Test: testing-plan T4.
[x] 8 · The scenarios. Write cli/tests/test_channels_outbox_integration.py with Gherkin docstrings: the report's full ask → queue → recover → deliver walk, and the status surface. Requirements: all. Test: testing-plan T4, T5.
[x] 9 · The capability docs. Update docs/capabilities/channels.md (the outbox, the drain, the status line) and docs/capabilities/observability.md if the new events belong in its list. Requirements: R3.1, R4.1. Test: testing-plan T12.
[x] 10 · Verify and record. Run the matrix and write evidence/verification.md, self-review.md, security-review.md and documentation.md. Requirements: all. Test: testing-plan T1–T12.