The default `busy_input_mode: interrupt` now redirects the live turn instead
of hard-stopping it and re-queuing a fresh turn, wired consistently across
every first-party surface via the shared core primitive.
- CLI, gateway (busy + PRIORITY paths), TUI (`_handle_busy_submit`), desktop
(`session.redirect` RPC), and ACP call `redirect()` when the agent advertises
`_supports_active_turn_redirect`, and fall back to the proven interrupt +
next-turn queue for older runtimes.
- Redirect is gated to plain text with no attachments: captioned or
attachment-bearing events (including adapters that classify unknown media as
`TEXT`) stay queued so media is never dropped.
- ACP `cancel()` records the interrupted prompt, sets its cancel event, and
hard-stops the agent while holding `runtime_lock`, closing the
cancel-then-correct ordering gap; connection I/O happens after the lock is
released.
- Desktop appends the correction as a real user transcript message so the live
view matches the durable history after reload.
- `/busy` help, onboarding hints, and the new `session.redirect` RPC describe
the redirect behavior; `/stop` remains the hard stop.
Extends PR #21400's resource inlining with image-specific handling: ACP
resource_link and embedded blob resources with an image/* mime (or image
file suffix when mime is missing) now emit an OpenAI image_url part
with a base64 data URL, so vision models actually see the image
instead of a [Binary file omitted] note. Non-image resources keep the
existing text-inlining behavior.
Adds 3 tests: local PNG via resource_link, JPEG mime inferred from
suffix when client omits mimeType, and embedded blob PNG.
When a user types /steer <text> on an ACP session that isn't actively
running a turn (and there's no interrupted-prompt salvage available),
_cmd_steer silently appended to state.queued_prompts and replied
"No active turn — queued for the next turn". That looks identical to
/queue output even though the user never typed /queue — @EddyLeeKhane
reported this as "/steer never works, gets queued instead".
Rewrite the payload to a plain user prompt before the slash-intercept
fires, matching the gateway's idle-/steer fallthrough in
gateway/run.py ~L4898.
