Document safe BB CLI automation workflows

[ryanbbrown]

Human comments

What was wrong

The built-in bb-cli skill did not explain five current operating contracts that live help alone does not make safe for automation: argv-only generated message text, per-command JSON shapes, provider-specific permission modes, sender attribution for queued agent messages, and terminal output loss after process exit. A Papercut triage found 65 original occurrences across these five patterns.

What changed

• Adds quoted staged-file forms for generated thread spawn and thread tell text, including the shell argument-size limit.
• Tells callers to inspect each command's JSON shape and the selected provider's live permission capabilities.
• Directs queued agent-to-agent reports through thread tell --mode queue, which preserves sender attribution, instead of an unattributed queue draft.
• Separates interactive, user-inspectable native terminals from output that must survive process exit.

This intentionally omits the earlier errored-thread workaround because #2715 fixed default thread tell recovery before this change.

How you verified

Reviewed installed BB 0.41.0 help and behavior, then checked current main at cffc82ad4db651f6dad600db33528df4e87348eb against the command registrations, thread-send logic, queued-message sender handling, provider capabilities, and terminal output lifecycle.

• Focused skill tests — 17 passed
• Turbo CLI/server tests — 280 files and 2,705 tests passed; 1 file skipped
• Turbo CLI/server typecheck — 6 tasks passed
• git diff --check

Related to #2620, #2622, and #2520.

AGENT GENERATED