Add Remote Progressive Preview node and run every mapped item (#9)

* Expect resolved STRING type for ModalMapInput boundaries

69a33e3 made _remote_output_io_type resolve wildcard "*" outputs through
their linked input, so a ModalMapInput boundary fed by a STRING list now
reports STRING, matching the mapped_input type the test already expects.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Add Remote Progressive Preview node

A local PreviewImage-style node that shows one empty slot per mapped item
when remote work starts and fills each slot as soon as that item's images
stream back, instead of waiting for ComfyUI to deliver the whole result.

- Planning records direct consumers as progressive_preview_target_node_ids
  and exempts them from local bridge materializers.
- The remote shim streams boundary outputs for those targets; mapped item
  payloads carry map_item_count and dispatch emits a start event.
- The host saves streamed images to temp, records them per prompt/node, and
  sends modal_progressive_preview websocket events.
- The node reuses streamed slots on final execution and only materializes
  bridge refs that were never streamed.
- web/progressive_preview.js renders the slot grid and hands off to the
  native preview on the final executed event.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Execute every mapped item instead of reusing shared-session outputs

Mapped items share one remote session. The restored-session short-circuit,
meant for identical per-lane seed phases, looked outputs up by node id
only, so after the first item on a container every later item skipped
sampling and returned that earlier item's image under its own bridge key.
Payloads carrying map_item_index now always execute.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Keep finished progressive previews handed off to the native preview

Hide the panel with an inline display style so the frontend's DOM-widget
wrapper cannot override the hidden attribute, and ignore replayed events
for a prompt whose final images were already delivered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/LEARNINGS.md

@@ -904,3 +904,24 @@ is still listed.
 `COMFY_MODAL_EXECUTION_MODE` used to default to `local`. That mode runs rewritten components inside the local ComfyUI process, and users who forgot to set the variable kept landing in it. They saw confusing failures, such as `/assets/...` model paths that only exist in remote storage. `settings.configured_execution_mode()` now owns the default (`remote`), and every host-side reader goes through it.
 
 Modal containers never set the variable, so their code relied on the old default to behave as local in-process workers: custom-node sync off, no nested Modal dispatch. The Modal image environment now pins `COMFY_MODAL_EXECUTION_MODE=local` explicitly, as SSH and Vast workers already did. Any new worker runtime must do the same, or it inherits the host default and may try to dispatch remotely from inside a worker.
+
+
+## Progressive previews bypass ComfyUI's list scheduling (2026-11-06)
+
+ComfyUI only runs a node once the upstream node has produced its entire output. A mapped proxy finishes only after every item, so no downstream node can show per-item results while the mapped run is in progress. Progressive display must ride the remote stream, not ComfyUI's data flow. The remote shim already published `boundary_output` stream events as each node finished, and mapped item payloads already carried `map_item_index`. `RemoteProgressivePreview` builds on that:
+
+- Planning records direct consumers as `progressive_preview_target_node_ids` on the boundary output. The key is serialized only when non-empty, so payload fingerprints and exact-payload tests are unchanged for workflows that do not use the node.
+- Mapped dispatch sends a `start` event with the item count before any item runs. Item payloads carry `map_item_count`.
+- The host saves each streamed IMAGE to temp, records it in `PROGRESSIVE_PREVIEW_REGISTRY` keyed by `(prompt_id, node_id)`, and sends a `modal_progressive_preview` websocket event.
+- The node is `is_input_list=True`, so one call sees every item. It gets the prompt id from `comfy_execution.utils.get_executing_context()`. ComfyUI v3 hidden inputs expose the prompt dict, not its id.
+
+Related bug found while investigating (not yet fixed): `_rewrite_hybrid_split_proxies` ignores `local_materializer_node_id` and session routes. A plain `PreviewImage` beside a remote continuation of a hybrid static/mapped component therefore receives bridge-ref dicts and fails in `save_images` with `KeyError: 0`. The progressive node avoids this because the planner exempts it from materializers and it materializes refs itself.
+
+
+## Mapped items silently reused one item's output (2026-11-06)
+
+`_short_circuit_restored_session_output_subgraph` (cloud and host fallback) skips execution when the remote session already holds a value for every session-backed boundary output. It looks that value up by `(session_id, node_id, output_index)`. It was added for per-lane static seed phases, whose outputs really are identical. Mapped items, however, share one remote session by design. Once one item on a container had produced node 9's IMAGE, every later item on that container found that value, skipped sampling (about 2 s instead of 30 s, with zero progress events) and returned the earlier item's image under its own, distinct bridge key. Downstream remote consumers, such as per-item SaveImage, and local previews all received duplicates. It surfaced only because the progressive preview showed streamed slots that differed from the final images.
+
+Symptoms to look for: per-item stream summaries with `progress_event_count=0` and short durations, and the container log line `Skipping prompt_executor_execute ... session-backed outputs were restored`. The fix: payloads that carry `map_item_index` never take the shortcut. Seed payloads carry no item index and keep it.
+
+Separately, a DOM widget's `hidden` attribute can lose to inline styles set by the frontend's widget wrapper. The progressive panel now hides itself with an inline `display: none`, and it ignores replayed events for a prompt it has already finalized.