The U1 printer panel: three cards, an ACE mode row and a toolhead gri…

.gitignore

@@ -41,4 +41,6 @@ resources/profiles/user/default
 deps_src/build/
 .claude/
 .hermes/
-CLAUDE.md
+CLAUDE.md
+# UI reference snapshots — third-party imagery, design reference only (see the folder's README)
+ui-snapshots-inspiration/

docs/ace-mmu/15-printer-panel.md

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+# The U1 printer panel (Prepare / Preview)
+
+Interactive mockup: [printer-panel-mockup.html](printer-panel-mockup.html) ·
+Visual standard: [16-ace-visuals.md](16-ace-visuals.md)
+
+> **Status: design only. No code has landed.** This branch carries the docs and mockups;
+> every implementation step below is still to do. The ACE machinery referenced here —
+> `ace_head_capacity` / `ace_head_unit`, `AceMmuProvider`, `sync_ace_topology`,
+> `AceMmuPlan` — lives on `feat/ace-mmu-slicing` and does not exist on
+> `develop/add-multiace-support` yet. Start from [NEXT.md](NEXT.md).
+
+**Prepare and Preview share one sidebar.** The Printer section at the top of it is a
+single widget seen in two tabs, so this is one change in two places — and anything
+added to it is also on screen while reading a sliced preview, where vertical space is
+contested.
+
+## What is wrong today
+
+Measured by running the app, not by reading it (`.claude/tools/start.sh headless`).
+
+| # | Defect | Where |
+|---|--------|-------|
+| 1 | **Four tabs hold one control each.** `Nozzle 1..4`, each with a `Diameter` combo; changing any one writes all four and switches the whole preset, because the U1 refuses mixed diameters. Three tabs exist to be clicked and show nothing new. | `Sidebar::update_nozzle_settings`, Plater.cpp:8682 |
+| 2 | **Three names for one thing.** Sidebar says *Nozzle 1–4*, Printer Settings says *Toolhead 1–4*, the assignment dialog says *T1–T4*. | Plater.cpp:8814, Tab.cpp:4808, `resources/web/aceplan` |
+| 3 | **No topology.** The preset knows head 4 is fed by ACE 1 with four slots (`ace_head_capacity`, `ace_head_unit`); the panel never says so. | — |
+| 4 | **No contents, and no way to ask.** The spool colours at each head are known when the printer is on the LAN — they already drive the filament sync — but never reach this panel. | `append_ace_filament_list`, Plater.cpp:773 |
+| 5 | **Two half-syncs.** The sidebar glyph syncs nozzle diameters only; multiACE topology sync is a separate button buried in Printer Settings › Multimaterial. | Plater.cpp:2214, Tab.cpp:4652 |
+
+## The shape: Bambu's panel, for four heads
+
+Taken from `ui-snapshots-inspiration/Nozzle_and_filament_info/`, piece by piece.
+
+- **Three cards across the top** — printer (thumbnail over preset combo), plate
+  (texture swatch + ⓘ, absorbing today's `Bed type` row), and **Sync info**.
+- **A green corner tick** on any card that agrees with the connected machine. On a head
+  box it means the ACE wiring matches what the printer reports — a claim we can make,
+  because `sync_ace_topology` already computes exactly that diff.
+- **A bordered box per head**, Bambu's Left/Right Nozzle panes wrapped **2×2**: an
+  `ACE` row (badge when a unit feeds it, `Stock feeder` otherwise, adjust button always)
+  and a `Diameter` row. No `Flow` row — this fork deleted the control and there is no
+  setting behind it.
+- **One `Nozzle` row**, not four tabs. Per-head diameters return only if the U1 ever
+  allows mixed sets; a machine reporting differing diameters still routes to the
+  existing `NozzleDiameterSelectDialog`.
+- **Sync in two steps** — *Successfully synchronized nozzle, ACE mode and ACE unit
+  information* → **[Continue to sync filaments] [Cancel]**, anchored over the viewport.
+  Step two opens the existing `Sidebar::show_sync_filament_dialog`.
+
+## ACE mode — the printer's own switch
+
+Verified against firmware (`/printer/gcode/help` on 192.168.2.242):
+
+```
+SET_ACE_MODE MODE=normal|multi|head [HEAD=n]
+ACE_SET_HEAD_ACE     HEAD=0..3 ACE=0..3   "each ACE head is wired to exactly one ACE"
+ACE_SET_HEAD_FEEDER  HEAD=0..3 ENABLE=0|1 "(head mode only)"
+```
+
+The panel mirrors it as a labelled dropdown — **Normal** / **Per toolhead** /
+**Combined** — with the raw `SET_ACE_MODE MODE=…` in the tooltip. Only in **head** mode
+does per-toolhead wiring mean anything, so the head boxes grey their ACE rows in Normal.
+Sync info reads the mode back along with the wiring.
+
+## The assign popover
+
+A **choice**, not a count: the firmware offers exactly two macros, so the list has
+exactly two kinds of row and a tick rather than a spinner.
+
+```
+Which ACE feeds Toolhead 4?
+  ⬡  Stock feeder            One spool, loaded at the head          ( )
+  ▤  ACE 1 · ACE 2 Pro       4 slots · connected · 39% RH           (✓)
+```
+
+Units are named as the printer names them — `protocol: "v2"` → **ACE 2 Pro**, `"v1"` →
+**ACE Pro** — the same mapping `resources/web/multiace/index.html` already uses. Between
+them the rows write exactly `ace_head_capacity` and `ace_head_unit`.
+
+**One unit may feed several heads.** `ACE_SET_HEAD_ACE` binds a head to one ACE; it says
+nothing about an ACE feeding one head, and `head_ace` is a map from head to unit. Ticking
+the same unit on a second head is therefore legal, each row then reads *also feeds
+Toolhead N*, and a warning states the real capacity.
+
+## Two defects this uncovered
+
+1. **A shared unit double-counts capacity.** `AceMmuPlan.hpp` sums capacity per head
+   (`total_cap += cap[h]`) and enforces it per head (`if (++load[h] > cap[h])`). Two
+   heads on one 4-slot unit read as **8 places** when there are 4, so the
+   infeasible-plate refusal — whose whole purpose is catching this — would pass a plate
+   that cannot be laid out. Needs a per-unit pool constraint beside the per-head one.
+2. **Combined mode cannot be emitted.** `ace_head_capacity` already offers *6 slots* and
+   *8 slots*, but `GCode.cpp`'s `unit_of_head()` returns the single `ace_head_unit[h]`
+   and the plan's slot is an index *within the head*. Slot 5 of an 8-slot head emits
+   `ACE=<first unit> SLOT=5` where the machine needs `ACE=<second unit> SLOT=1` — wrong
+   unit, wrong slot, wrong colour. Those enum values are unsafe until the emitter maps
+   slot → (unit, slot).
+
+## Touch points
+
+| Piece | Where | State |
+|-------|-------|-------|
+| The panel | `Plater.cpp:2199–2565` | Title bar, preset card, Bed type row, nozzle notebook — built once in the Sidebar constructor |
+| The head boxes | `Sidebar::update_nozzle_settings`, `Plater.cpp:8682` | Rebuilds one page per `nozzle_diameter` entry; becomes a 2×2 grid |
+| Sync, nozzles | `Plater.cpp:2214–2350` | Queries the machine, `NozzleDiameterSelectDialog` on mixed diameters. Keep; becomes half the press |
+| Sync, topology | `TabPrinter::sync_ace_topology`, `Tab.cpp:4652` | Reads `/multiace/api/state`, diffs per head, reports. Lift out of `TabPrinter` so the sidebar can call it |
+| Sync, filaments | `Sidebar::show_sync_filament_dialog`, `Plater.cpp:8467` | Already lists U1 toolheads *and* ACE slots. What *Continue to sync filaments* opens |
+| Topology | `ace_head_capacity`, `ace_head_unit` | Per-head `coInts` in the printer preset — the panel works with the printer off |
+| Live contents | `AceMmuProvider`, `AceSnapshot` | Units, slots, colours, humidity, per-head bindings. One `fetch_once()` |
+
+**Before building:** the U1 connects as a `PrintHost` through the webview, not as a
+`MachineObject`, so this panel cannot lean on `MachineObject::poll_ace_ams()`. It
+resolves a host with `AceMmuProvider::resolve_connected_host()` and reads on demand —
+the other reason press-to-sync fits the U1 better than a background poll.
+
+## Shipping order
+
+Each is one branch off `develop/add-multiace-support`, one squashed PR.
+
+1. **Panel structure** — three cards, 2×2 head boxes, one Nozzle row, `Toolhead N`
+   naming, plate card absorbing Bed type. No ACE; no new config. Self-contained.
+2. **Topology in the preset** — `ace_head_capacity` / `ace_head_unit`, the Multimaterial
+   settings page, `sync_ace_topology`.
+3. **The panel's ACE row** — badge, assign popover, ACE mode dropdown, on top of 1 + 2.
+4. **Sync info, two-step** — nozzle + topology in one press, chaining to the filament sync.
+5. **Per-unit capacity pool** — the shared-unit fix. Before any user can share a unit.
+6. **Combined mode** — the emitter's slot → (unit, slot) map. Until then the mode is
+   listed and disabled, with the reason on it.