spec(047): Phase 3 finish — honest scope accounting (deferred/not-attempted)

Replaces the "100% V1 dispatch coverage now reached" claim in the
tracker with the precise statement: every typed-items host family
scoped by Phase 3's batch list has a V1 descriptor. Adds an explicit
"Phase 3 deferred / not-attempted" enumeration to both §14 and the
tracker covering the long tail that was never on the Phase 3 batch
list — ContentDialog / Flyout / Popup family, navigation /
title-bar / media family, ItemsView / ItemContainer / plain
GridViewElement, interop + a11y wrappers, and the Reactor
composition primitives that likely should stay out of the V1
handler protocol entirely.

Also flags TemplatedFlipViewElement<T> as the one genuine engine
gap still carried from Phase 3 close-out (FlipView lacks
ContainerContentChanging; would need a PreMountedItems
ChildrenStrategy). The intermediate base
TemplatedFlipViewElementBase is reserved in the element hierarchy
for that future port.

No code changes — docs accuracy only.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: codemonkeychris

docs/specs/047-extensible-control-model.md

@@ -1431,7 +1431,9 @@ ARM64 stable-AC re-capture on `LAPTOP-4MEP83VI` remains deferred for the §14 ra
 
 - **Port (7) ItemsRepeater<T>** — new `ItemsRepeaterElementBase` + `ItemsRepeaterElement<T>` records modeled on `LazyStackElementBase` (the base implements `IKeyedItemSource` + `IItemsRepeaterFactorySource` so it flows through Engine (1)'s arm without new engine work). Distinct from Lazy*Stack: no hard-coded `StackLayout` (nullable `Layout` property — author supplies any `WinUI.Layout`) and no implicit `ScrollViewer` wrap (host externally for scrolling). Legacy `MountItemsRepeater` / `UpdateItemsRepeater` arms added for V1 OFF parity (there was no legacy arm before — the element type is new). DSL surface: `ItemsRepeater<T>(items, keySelector, viewBuilder)` factory in `Dsl.cs` matching `LazyVStack` / `LazyHStack`. Single base-derived descriptor on `ItemsRepeaterElementBase` catches every closed-T variant via `RegisterHandlerForDerivedTypes`.
 
-**Phase 3 finish carry-forwards:** none remaining — every typed-items host has a V1 descriptor and the engine surface is complete. Production swap (Phase 4 cleanup) registers each descriptor in `RegisterV1BuiltInHandlers` and deletes the matching legacy `MountXxx` switch arm.
+**Phase 3 finish carry-forwards:** none remaining for the typed-items host families that were on Phase 3's scope (LazyVStack/HStack, ItemsRepeater<T>, ListView<T>, GridView<T>, TreeView, FlipView (simple), TabView, Pivot). The engine surface is complete. Production swap (Phase 4 cleanup) registers each descriptor in `RegisterV1BuiltInHandlers` and deletes the matching legacy `MountXxx` switch arm.
+
+**Phase 3 deferred / not-attempted** (recorded for the Phase 3.5 / Phase 4 prelude — element types in the legacy `Reconciler.Mount` switch that have neither a Phase 1 V1 handler nor a Phase 3 descriptor; see `tasks/047-extensible-control-model-implementation.md` for the full enumeration). One genuine carve from close-out remains: `TemplatedFlipViewElement<T>` (the typed FlipView peer — needs a `PreMountedItems` ChildrenStrategy since FlipView lacks `ContainerContentChanging`). The rest of the deferred list — `GridViewElement` (plain), `ItemsViewElementBase`, dialog / overlay family (`ContentDialog`, `Flyout`, `Popup`, `MenuBar`, `MenuFlyout`, `CommandBar`, `CommandBarFlyout`), heavy / specialized controls (`WebView2`, `NavigationView`, `TitleBar`, `MediaPlayerElement`, `AnimatedVisualPlayer`, `MapControl`, `SemanticZoom`, `AnnotatedScrollBar`, `RefreshContainer`, `SwipeControl`, `ParallaxView`), interop / a11y (`SemanticElement`, `AnnounceRegion`, `XamlHost`, `XamlPage`, and the already-escape-hatched `IconElement`), and Reactor composition primitives (`Component`, `Func`, `Memo`, `ErrorBoundary`, `CommandHost`, `Validation.*`) — was never on the Phase 3 batch list. The composition primitives likely should NOT route through the V1 handler protocol (they sit above it); the rest are straightforward descriptor ports (or, where they'd surface engine gaps, would follow the close-out / finish pattern of landing the engine extension before the port).
 
 **Phase 3 finish advisory perf** — Cloud PC x64 re-capture under `docs/specs/047/phase3-results/CPC-ander-YTZ3O-x64-advisory/2026-05-28-phase3-finish-3x5/` (n=15, 3 launches × 5 reps). V1 ON (descriptors) vs V1 OFF (today), against prior `2026-05-27-phase3-closeout-3x5/`:
 

docs/specs/tasks/047-extensible-control-model-implementation.md

@@ -920,10 +920,22 @@ carve-outs:
       added (the element type is new — there was no legacy arm before).
       DSL surface: `ItemsRepeater<T>` factory in `Dsl.cs`. Single
       base-derived `ItemsRepeaterDescriptor` catches every closed-T
-      variant. 11 new fixtures (Desc_ItemsRepeater_*). 100% V1 dispatch
-      coverage now reached.
+      variant. 11 new fixtures (Desc_ItemsRepeater_*). Every typed-items
+      host family scoped in Phase 3 now has a V1 descriptor (the
+      precise close-out claim — the broader "every Element type"
+      audit is captured under the "Phase 3 deferred / not-attempted"
+      section below).
 - [x] **G3 typed lists — `TreeView`, `FlipView`, `TabView`, `Pivot`** —
-      closed by Phase 3 finish.
+      closed by Phase 3 finish. **Note:** "FlipView" here is the
+      simple non-templated `FlipViewElement` (Element[] items). The
+      typed `TemplatedFlipViewElement<T>` peer stays carved exactly
+      as documented at Phase 3 close-out — FlipView lacks
+      `ContainerContentChanging` so the realization pipeline used by
+      `TemplatedListView<T>` / `TemplatedGridView<T>` doesn't apply;
+      a `PreMountedItems` strategy would land it but no fixture
+      currently demands it. The intermediate marker base
+      `TemplatedFlipViewElementBase` is reserved in the element
+      hierarchy for that future port.
       - **TreeView** via new `TreeChildren<TElement, TControl>`
         strategy (hierarchical, positional rebuild on Update,
         recursive `ContentElement` mount).
@@ -939,6 +951,51 @@ carve-outs:
       - 29 new fixtures across the four descriptors (Desc_TreeView_*,
         Desc_FlipView_*, Desc_TabView_*, Desc_Pivot_*). Total Desc_
         baseline: 602 ok / 0 failures both V1 ON and V1 OFF.
+        (Total grows to 613 after Port (7) ItemsRepeater<T> above.)
+
+**Phase 3 deferred / not-attempted** (element types in the legacy
+`Reconciler.Mount` switch that have neither a Phase 1 V1 handler nor a
+Phase 3 descriptor — out of scope for the Phase 3 batch list, recorded
+here for a future Phase 3.5 / Phase 4 prelude). Cross-referenced from
+the audit at the end of `spec/047-phase3-finish`:
+
+- **Genuine engine gap:** `TemplatedFlipViewElement<T>` — close-out
+  carve. Needs a `PreMountedItems` ChildrenStrategy. The intermediate
+  base `TemplatedFlipViewElementBase` already exists for the
+  base-derived registration.
+- **Untyped items hosts not ported:** `GridViewElement` (the plain
+  Element[] variant — `ListViewElement` got a Phase 1 V1 handler,
+  GridView did not), `ItemsViewElementBase` (the higher-level
+  `ItemsView` wrapping its own ItemsRepeater), `ItemContainerElement`.
+- **Dialog / overlay family:** `ContentDialogElement`,
+  `FlyoutElement`, `PopupElement`, `MenuBarElement`,
+  `MenuFlyoutElement`, `CommandBarElement`,
+  `CommandBarFlyoutElement`. Button-family `Flyout` ships through the
+  `.OneWayBridged` setter on the button descriptors; the standalone
+  flyout elements are their own legacy paths.
+- **Heavy / specialized controls:** `WebView2Element`,
+  `NavigationViewElement`, `NavigationHostElement`,
+  `TitleBarElement`, `MediaPlayerElementElement`,
+  `AnimatedVisualPlayerElement`, `MapControlElement`,
+  `SemanticZoomElement`, `AnnotatedScrollBarElement`,
+  `RefreshContainerElement`, `SwipeControlElement`,
+  `ParallaxViewElement`.
+- **Polymorphic / interop / a11y:** `IconElement` (already documented
+  as escape-hatched — polymorphic mount), `SemanticElement`,
+  `AnnounceRegionElement`, `XamlHostElement`, `XamlPageElement`.
+- **Reactor infrastructure (likely SHOULD stay out of V1 dispatch):**
+  `ComponentElement`, `FuncElement`, `MemoElement`,
+  `ErrorBoundaryElement`, `CommandHostElement`, `ModifiedElement`,
+  `Validation.FormFieldElement` /
+  `ValidationVisualizerElement` / `ValidationRuleElement`. These are
+  Reactor composition primitives, not WinUI control wrappers — they
+  sit above the V1 handler protocol rather than being consumers of
+  it.
+
+The "100% V1 dispatch" goal as scoped by §14's Phase 3 batches IS
+met (every batch entry has a V1 handler or descriptor). The list
+above is genuine post-Phase-3 scope, not a regression against the
+shipped Phase 3 plan.
 
 **Carry-forward known defects** (from Phase 1):