feat(ui): add Unity 6 UI Toolkit authoring and verification

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## [Unreleased]
+
+### Added
+
+- Added the Unity 6+ `ucp ui` family for agent-driven UI Toolkit work: target discovery, importer- and clone-backed UXML/USS/TSS linting, bounded resolved-tree and binding inspection including physical control children and realized ListView rows, DPI-correct Editor-panel PNG capture, and an end-to-end multi-state `ui check` workflow.
+- Added strict `.ucp-ui.json` scenarios with JSON data overlays, allowlisted fixture mutations, eager `repeat` templates, and harness-owned virtualized `ListView` binding for reproducible dynamic layouts.
+- Added conservative UI audits with complete diagnostic totals, error-prioritized bounded details, and exemptions for Unity internal focus targets; lint inspects immutable package artifacts without forced reimport.
+- Added UI operation interruption reporting, status recovery on CLI timeouts, and a render timeout default that accommodates the bridge's overall duration limit.
+- Added focused Rust, bridge, fixture, lint, inspector, and audit coverage plus agent-facing UI Toolkit workflow documentation.
+
 ## [0.6.2] - 2026-08-31
 
 ### Added
@@ -576,4 +586,3 @@
 - JSON-RPC 2.0 protocol
 - Lock file discovery mechanism
 - Per-session token authentication
-

README.md

@@ -95,6 +95,10 @@ A few things that are awkward or impossible without it:
 - **Profile programmatically.** Run a session, then read the hierarchy sorted by self time, with
   `--fields` to keep the payload small and truncation reported as "showing 50 of 4,312".
 
+### UI Toolkit authoring loops
+
+Lint UXML and USS with Unity's own importers, populate repeaters and virtualized lists from strict JSON scenarios, inspect resolved layout and bindings, and capture deterministic panel screenshots. `ucp ui check` runs the complete lint-to-visual-verification pass without loading or dirtying a scene.
+
 <br>
 
 ## Install

cli/src/commands/mod.rs

@@ -28,6 +28,7 @@ pub mod snapshot;
 pub mod spatial;
 pub mod tests;
 pub mod transform;
+pub mod ui;
 pub mod vcs;
 pub mod view;
 
@@ -389,6 +390,11 @@ pub enum Command {
         #[command(subcommand)]
         action: view::ViewAction,
     },
+    /// Inspect, lint, and render UI Toolkit UXML and USS
+    Ui {
+        #[command(subcommand)]
+        action: ui::UiAction,
+    },
 }
 
 /// Run editor-side automation scripts (Playwright-like). A script is an editor class implementing
@@ -971,5 +977,6 @@ pub async fn run(cmd: Command, ctx: Context) -> anyhow::Result<()> {
         Command::Transform { action } => transform::run(action, &ctx).await,
         Command::Spatial { action } => spatial::run(action, &ctx).await,
         Command::View { action } => view::run(action, &ctx).await,
+        Command::Ui { action } => ui::run(action, &ctx).await,
     }
 }