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status: Active owner: iced-migration track created: 2026-04-20 supersedes: — related:

• ../2026-04-14_iced_host_migration_execution_plan.md
• ../2026-04-20_navigation_policy_plan.md (archived)
• ../2026-04-20_node_style_configurability_sweep_plan.md (archived)

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Follow-on to the navigation-policy and node-style sweeps. Same pattern (portable struct + per-view override + per-graph default + host-neutral resolver), applied to two new surfaces: physics release behavior, and shell chrome theming.

The navigation-policy sweep proved the three-slot resolver pattern: resolve_X(view_id) returns view override ? per-graph default ? preset fallback. Carrying that through iced M3.5 means the iced host can reuse the same resolver calls without re-deriving from egui state.

Two surfaces carried hardcoded constants that would have forced the iced host to replicate opinionated defaults:

1. SimulateMotionProfile — release-impulse tuning for drag→fling was inlined at graph/scene_runtime.rs:236 with an app-local duplicate struct.
2. Shell chrome colors — status dots, workbench panel background, and the high-contrast selection-highlight trio were Color32::from_rgb literals scattered across four files.

Both are user-visible defaults that a hosting embedder (iced, future wgpu-native) will want to override without patching the shell.

• crates/graph-canvas/src/scene_physics.rs — SimulateMotionProfile gained Serialize + Deserialize + Default. Default derives from SimulateBehaviorPreset::default() so serialized forms round-trip.
• app/graph_views.rs — GraphViewState gained simulate_motion_override: Option<SimulateMotionProfile> with #[serde(default)]. Added resolve_simulate_motion_profile(view_id), set_graph_view_simulate_motion_override, set_simulate_motion_default on GraphBrowserApp.
• domain/mod.rs — DomainState.simulate_motion_default: Option<…> added; both constructor sites updated.
• graph/scene_runtime.rs:236 — call site swapped from inlined struct to app.resolve_simulate_motion_profile(view_id).
• render/canvas_bridge.rs — three tests:
  • resolve_simulate_motion_profile_falls_back_to_preset
  • resolve_simulate_motion_profile_prefers_view_override
  • resolve_simulate_motion_profile_falls_back_to_per_graph_default

• app::graph_views::SimulateBehaviorPreset and graph_canvas::scene_physics::SimulateBehaviorPreset are still duplicated. resolve_simulate_motion_profile does a manual match to bridge them. Dedup deferred — touches more surface than this sweep warranted.

Six new tokens added to ThemeTokenSet in shell/desktop/runtime/registries/theme.rs, wired across all four theme variants (default / light / dark / high_contrast):

• status_warning, status_neutral — paired with existing status_success for the three-state sync-status dot.
• workbench_panel_background — the (20, 20, 25) chrome-fill that recurred at four frame call sites.
• selection_highlight_background / selection_highlight_text / selection_highlight_stroke — the high-contrast-theme trio previously inlined in egui Visuals.

• shell/desktop/ui/workbench_host.rs — graph_scope_sync_status now resolves status_neutral / status_warning / status_success from theme tokens.
• shell/desktop/ui/gui_frame/post_render_phase.rs — both SidePanel::right("workbench_area") and CentralPanel::default() frames now pull workbench_panel_background from the active theme.
• shell/desktop/workbench/tile_render_pass.rs:1391 — run_tile_render_pass CentralPanel frame swapped.
• shell/desktop/ui/toolbar/toolbar_ui.rs — render_fullscreen_origin_strip derives its translucent fill from workbench_panel_background + alpha 220, instead of the literal.
• shell/desktop/ui/gui.rs — apply_runtime_theme_visuals high-contrast branch now reads the three selection-highlight tokens instead of inlining from_rgb(255, 230, 0) / WHITE / BLACK.

All four theme variants resolve to values that preserve visual parity with the prior hardcoded defaults (default theme uses the same rgb triples that were inlined).

• Minimap palette — shell/desktop/ui/overview_plane.rs has ~12 Color32::WHITE / literal-rgb sites clustered around the overview rendering. They share one visual semantic (minimap foreground) and belong in a dedicated minimap_* token pass.
• Divider stroke tokens — 8 sites in gui_frame/* and the workspace swatch use Stroke::new with ad-hoc grays. Group into divider_stroke_primary / _subtle in a follow-on.
• NodeStyle color-picker UI — the node-style sweep landed the policy surface but didn't wire an egui color_edit_button_rgba control for end users. Follow-on UX-layer task.

Both lifts feed directly into the M3.5 carve-out in ../2026-04-14_iced_host_migration_execution_plan.md. When the iced host renders the workbench frame or simulates release impulse, it calls the same resolver methods on GraphBrowserApp — no bespoke defaults to re-derive. That closes the two outstanding items noted in the M3 completion log.

• SimulateMotionProfile portable with Default + Serialize + Deserialize
• resolve_simulate_motion_profile on GraphBrowserApp with view-override + per-graph-default + preset-fallback semantics
• Three unit tests covering each resolver path
• Six new theme tokens wired in all four theme variants
• Five shell call sites swapped off Color32::from_rgb literals
• cargo check -p graphshell clean (warnings unchanged)
• cargo test -p graph-canvas --lib green (224 pass)
• Canvas-bridge resolver suite green (25 pass)
• Broader graphshell --lib default-features suite (2158 pass / 3 ignored)

• SimulateMotionProfile portability + resolver landed with tests.
• Theme palette tokens added; five call sites swapped.
• Deferred sweeps logged in §2.
• Iced M3.5 alignment noted in §3.