docs(product): spec Phase L L4 — dock-panel button layout enhancement

Capture+placement move to a top toolbar; Design View tag/switch verbs to the bottom toolbar; footer gains a narrow Arrange|Design toggle + a Tail button (was a click-zone), with warn Prune set apart at the right. Ungated/extension-side; sequences after the palette revision. Layout only.

CONTEXT.md

@@ -1512,6 +1512,51 @@ it. New layout math goes in a pure geometry module; `bank_grid`/`tab_strip`/`mod
 stay the pure source of truth for their own hit-testing. **L2 sequences after M11 merges**
 so it inventories the actual landed buttons.
 
+## L4 dock-panel button layout (top / bottom / footer re-home)
+
+L4 is a **second layout pass over the same `bank_panel`** that re-homes the L2 button inventory
+around *frequency and intent*. It ships **no new action and changes no capture/placement
+behavior** — every button fires an existing registered action; the "capture ≠ placement"
+load-bearing principle is untouched (the buttons only *fire* the split acts, they never fuse
+them). It is **ungated by Phase S** (the dock panel is on dev) and independent of L3.
+**L4 sequences AFTER the in-flight DS-2 palette-revision branch merges to dev** — both rework
+`bank_panel` heavily, and landing L4 concurrently would collide the same file. Drawn through the
+L1 kit in the DS-2 grey-neutral + three-accent-pastel palette (prune stays `warn`); no palette
+or font decisions are re-opened here.
+
+**The new three-zone structure:**
+
+- **Top toolbar = capture + placement.** The capture cluster (capture item, capture track,
+  batch items, batch razor, capture RT) and the placement cluster (insert, insert-conform) move
+  from the bottom L2 action bar to a **top** toolbar — the eye's first landing, matching the two
+  acts the tool exists for. Icon+label buttons with the keybinding as a `micro` sub-label (the
+  M11 keybinding-help convention), drawn through the kit.
+- **Bottom toolbar = Design View tagging + switching.** The space the capture/placement buttons
+  vacate holds the **Design View action family** as buttons: **tag / untag selected tracks for a
+  mode, activate Arrange, activate Design, toggle active mode, show-both.** These are the
+  registered Design View actions today; L4 gives them a button home here.
+- **Footer = narrow Arrange|Design toggle · Tail button · … · Prune.** The large top
+  `[ Arrange | Design ]` segmented toggle **shrinks to just-wide-enough-for-its-text** and moves
+  into the footer at the **left**, carrying its per-mode membership count as a compact adjacent
+  label. The **Tail** affordance is converted from a **click-zone to a proper kit button**
+  (rest/hover/pressed states; click still cycles the tail setting). **Prune** stays the
+  byte-deleting action — **set apart at the far right, `warn`-colored** — the only file-deleting
+  affordance, kept isolated so no benign toggle sits next to it.
+
+**Footer affordance order (left → right):** `[Arrange|Design]` toggle · Tail button · … ·
+**Prune** (rightmost, set apart, `warn`). The order reads benign/frequent at the left
+(view-mode toggle, tail-length control — both "how this panel/capture behaves") → destructive/
+rare at the right (Prune, isolated), so a mis-click near the left is cheap and the one
+destructive control is spatially and chromatically distinct.
+
+**Pure/shell discipline (unchanged).** All new toolbar-row and footer-strip layout math goes in
+pure CTest-covered geometry modules — **extend/mirror `action_bar`** (the toolbar row layout,
+now instantiated top and bottom) and **`mode_switch`** (the now-narrow, fit-to-text footer
+toggle geometry + hit-test). `bank_grid` and `tab_strip` remain the pure owners of their own
+surfaces' hit-testing. The L1 kit draws; the geometry stays pure. **L4 resolves its re-home
+against the post-palette-revision `bank_panel`** (build-time inventory once that branch is on
+dev).
+
 ## The L3 gate + Phase S coordination contract
 
 **L3 (VST editor + embed-strip restyle) is GATED on Phase S landing on dev.** The VST
@@ -1519,7 +1564,10 @@ editor (`IPlugView` LICE surface), the S6 embed strip, and the keyboard strip li
 Phase S, which is **not on dev yet** (it exists on the phase-s worktree). L3 cannot be
 built on dev until Phase S's editor/embed surfaces (≈ S1 / S6 / S10) merge to dev — **the
 Phase L team must not chase these files on dev; they are not there.** Until then L3 is a
-planned, blocked point; L1 and L2 are the live Phase L work.
+planned, blocked point; L1 and L2 have landed, and **L4 (dock-panel button layout enhancement)
+is the live, ungated extension-side Phase L work — it does not touch any Phase S surface, and
+sequences after the in-flight palette revision merges to dev** (shared-`bank_panel` collision).
+L4 is independent of the L3 gate.
 
 **Coordination contract (load-bearing):** Phase S's S10–S13 build their interaction UX with
 the **current** drawing and **adopt the L1 kit when it is available — they are NOT gated on

PLAN.md

@@ -288,7 +288,9 @@ build:** the `IReaperUIEmbedInterface` contract + embed message/lifecycle agains
 > have landed** — `theme`/palette module, `component_geometry` geometry/hit-test helpers,
 > `draw_kit` shell, GDI `DrawText` retirement in `bank_panel` (L1); `action_bar` pure
 > task-grouped layout module, full M11-aware button inventory placed by task cluster,
-> `bank_panel` redesigned through the L1 kit (L2). See `COMPLETED.md`. **L3 remains.**
+> `bank_panel` redesigned through the L1 kit (L2). See `COMPLETED.md`. **L3 and L4 remain**
+> — L3 gated on Phase S landing on dev; L4 (dock-panel button layout enhancement) ungated and
+> extension-side, sequencing after the in-flight palette revision merges to dev.
 >
 > **This section is self-contained for a team without Phase S context.** Where a point
 > touches a Phase S surface (the VST editor, the embed strip, the keyboard strip), the
@@ -365,15 +367,86 @@ work.
   state — never a pulse, per the speed constraint) as the signature surface; VST3 class UID
   unchanged. (Gated.)
 
+## L4 — dock-panel button layout enhancement (ungated, extension-side)
+**Goal:** Re-home the `bank_panel`'s L2 button inventory around *frequency and intent*, so the
+two acts the tool exists for (capture, placement) sit at the **top** where the eye lands, the
+Design View organize/switch verbs get a real button home at the **bottom**, and the footer
+carries the small persistent controls (the Arrange|Design toggle, Tail, Prune) in a coherent
+left-to-right order. This is a **layout re-home of buttons that fire existing actions** — no new
+actions, no capture/placement behavior change, no touching the "capture ≠ placement" principle.
+It is independent of L3 (which stays gated on Phase S); L4 is **ungated, extension-side only**
+(the dock panel lives on dev). Product framing: `docs/product/visual-design-language.md` §L4
+(new) + CONTEXT.md §Phase L "L4 dock-panel button layout".
+
+The four layout moves (Daniel, 2026-07-26):
+1. **Capture + placement clusters move to a TOP toolbar.** The capture cluster (capture item,
+   capture track, batch items, batch razor, capture RT) and the placement cluster (insert,
+   insert-conform) leave the current bottom L2 action bar and become a **top** toolbar — the
+   first thing the eye meets, matching their frequency and the tool's purpose.
+2. **The bottom toolbar is repurposed for Design View tagging + switching.** In the space the
+   capture/placement buttons vacate, place the Design View action family as buttons: **tag /
+   untag selected tracks for a mode, activate Arrange, activate Design, toggle active mode,
+   show-both.** These are registered actions today (the Design View action family); L4 gives
+   them a button home in the bottom toolbar.
+3. **The Arrange|Design segmented toggle shrinks and moves to the footer.** The large top
+   `[ Arrange | Design ]` segmented control shrinks to **just wide enough for its text
+   comfortably** and moves into the **footer, to the LEFT of the Prune button** (see footer
+   order below). The per-mode membership count travels with it (as a compact adjacent label).
+4. **Tail becomes a real button.** The Tail footer affordance is a **click-zone** today
+   (clicking cycles the tail setting) — inconsistent with the other footer controls. Convert it
+   to a proper **button** drawn through the L1 kit like the others; click still cycles the tail
+   setting, but it now reads and behaves as a button (rest/hover/pressed states).
+
+**Footer affordance order (left → right):** `[Arrange|Design]` toggle · Tail button · … ·
+**Prune** (set apart at the right, `warn`). *Rationale:* the two view/session controls (mode
+toggle, tail) group at the left as the "how this panel/capture behaves" cluster; Prune stays
+isolated at the far right, visually separated and `warn`-colored, because it is the only
+byte-deleting affordance and must never sit adjacent to a benign toggle where a mis-click is
+cheap. Order reads left (benign, frequent) → right (destructive, rare).
+
+**Verify (in DAW):** the top toolbar fires every capture + placement action; the bottom toolbar
+tags/untags selected tracks and switches/toggles Arrange/Design/show-both; the footer shows a
+narrow `[Arrange|Design]` toggle at the left, a Tail button that cycles tail on click with
+button states, and the Prune button set apart at the right in `warn`; every surface draws
+through the L1 kit in the DS-2 grey+pastel palette; capture and placement still never
+auto-insert (the buttons only fire the existing, unchanged actions).
+
+**Depends on:** L1 (the kit) + L2 (the landed layout + `action_bar` module). **Ungated by Phase
+S** — extension-side (`bank_panel`) only. **Sequence AFTER the palette revision merges to dev**
+— the in-flight DS-2 grey+pastel palette branch also reworks `bank_panel` heavily; landing L4
+concurrently would collide the same file. L4 begins once the palette revision is on dev.
+**Pure/shell discipline (unchanged):** all new toolbar/footer layout math goes in pure
+CTest-covered geometry modules — extend/mirror `action_bar` (toolbar row layout) and
+`mode_switch` (the now-narrow footer toggle); `bank_grid`/`tab_strip` stay owners of their own
+surfaces' hit-testing. The kit draws; geometry stays pure.
+
+- [ ] Top toolbar: re-home the capture cluster (item / track / batch items / batch razor /
+  capture RT) + placement cluster (insert / insert-conform) from the bottom L2 bar to a top
+  toolbar (pure row layout in `action_bar`; kit draw). Buttons fire the existing actions
+  unchanged — no auto-insert.
+- [ ] Bottom toolbar: place the Design View action family as buttons (tag / untag selected for
+  mode, activate Arrange, activate Design, toggle active mode, show-both), firing the existing
+  registered Design View actions.
+- [ ] Footer: shrink the `[ Arrange | Design ]` segmented toggle to fit-its-text width and move
+  it to the footer left of Prune (narrow-segment geometry in `mode_switch`); carry the per-mode
+  count as a compact adjacent label.
+- [ ] Footer: convert the Tail click-zone into a proper kit button (rest/hover/pressed states;
+  click cycles the tail setting as today).
+- [ ] Footer order: `[Arrange|Design]` · Tail · … · Prune (`warn`, set apart at the right);
+  pure footer-strip layout covered by CTest.
+
 ## Phase L — sequencing
 ```
 L1 (shared kit) ──► L2 (dock-panel layout redesign) [LANDED]
-        └─────────► L3 (VST editor + embed-strip restyle; GATED on Phase S landing on dev)
+        ├─────────► L3 (VST editor + embed-strip restyle; GATED on Phase S landing on dev)
+        └─────────► L4 (dock-panel button layout enhancement; ungated, extension-side;
+                        sequences AFTER the palette revision merges to dev)
 
 Phase S (separate team, ungated): S-work builds with current drawing, adopts L1 when it lands.
 ```
-L1 and L2 have landed. L3 waits for Phase S to reach dev. Phase S feature work runs in
-parallel, ungated by Phase L.
+L1 and L2 have landed. L3 waits for Phase S to reach dev. L4 is ungated and extension-side but
+sequences after the in-flight palette-revision branch merges to dev (both rework `bank_panel`).
+Phase S feature work runs in parallel, ungated by Phase L.
 
 ## Phase L — must-verify-before-build
 - **LICE design-kit surfaces (L1)** — `LICE_GradRect`, `LICE_RoundRect`, AA
@@ -390,6 +463,11 @@ parallel, ungated by Phase L.
   useful; keep hit-test geometry pure regardless.
 - **M11 button inventory (L2)** — resolved at L2 build: inventory taken against dev after
   M11 merged; all buttons placed by task cluster in the landed `action_bar` module.
+- **L4 re-home surface (L4)** — resolved at L4 build against the **post-palette-revision**
+  `bank_panel`: confirm the landed `action_bar` row-layout module and the `mode_switch`
+  segmented-toggle geometry extend cleanly to a top toolbar + a narrow footer toggle, and that
+  the Design View action family's command ids are all live for the bottom-toolbar buttons.
+  **Do not build until the palette revision is on dev** (shared-file collision).
 
 ---