fix: present frames during continuous input

agents.md

@@ -90,8 +90,9 @@ Real and verified:
   macOS Metal toolchain so `cargo run`'s shader-build failure is fixed.
 - Scroll input: consecutive same-document wheel requests coalesce at the
   profile worker boundary while preserving total device-pixel distance;
-  clicks, text, and allow-once permission transfers retain strict ordering.
-  Verified by a blocked-worker burst regression and the live-site scroll e2e.
+  frames from the active render epoch remain presentable while newer input is
+  queued. Clicks, text, and allow-once permission transfers retain strict
+  ordering. Verified by generation, blocked-worker burst, and live-site tests.
 - Website color scheme: resolved System/Light/Dark state crosses sidecar
   protocol v4 and reaches `WebView::notify_theme_change`; GPUI appearance
   events trigger a shell repaint, and first-navigation WebView replacement

crates/ely_app/src/shell/web_surface_runtime.rs

@@ -104,9 +104,11 @@ impl WebSurfaceRuntime {
         let submitted_at = Instant::now();
         let started_loading = {
             let session = session_for_scope(&mut self.sessions, tab.id(), scope.clone());
-            let started_loading = session.started_loading(&requested_url, size, zoom_percent);
+            let started_loading =
+                session.started_loading(&requested_url, size, zoom_percent, self.color_scheme);
             if started_loading {
                 session.pending_user_navigation = false;
+                session.frame_generation_floor = Some(generation);
             }
             if user_navigation_input {
                 session.pending_user_navigation = true;
@@ -114,6 +116,7 @@ impl WebSurfaceRuntime {
             session.requested_url = requested_url.clone();
             session.size = size;
             session.zoom_percent = zoom_percent;
+            session.color_scheme = Some(self.color_scheme);
             session.scroll_offset = next_scroll_offset;
             session.generation = Some(generation);
             session.cadence.note_ensure(input_kind, started_loading, submitted_at);
@@ -296,7 +299,7 @@ impl WebSurfaceRuntime {
                         continue;
                     };
                     if !self.sessions.get(&tab_id_obj).is_some_and(|session| {
-                        &session.scope == scope && session.generation == Some(generation)
+                        &session.scope == scope && session.accepts_frame_generation(generation)
                     }) {
                         continue;
                     }

crates/ely_app/src/shell/web_surface_runtime_generation_tests.rs

@@ -145,6 +145,35 @@ fn late_frame_is_discarded_after_tab_session_closes() -> Result<(), String> {
     Ok(())
 }
 
+#[test]
+fn earlier_frame_from_same_render_epoch_remains_presentable() -> Result<(), String> {
+    let mut runtime = WebSurfaceRuntime::new_with_client_factory(empty_client_factory);
+    let tab_id = TabId::new();
+    let profile_id = ProfileId::new();
+    let tab = web_tab(tab_id.clone(), profile_id.clone(), "https://example.com/page")?;
+
+    runtime.ensure_tab(&tab, surface_size(), ProfileDataMode::Transient, &[], pending_input())?;
+    let earlier = current_generation(&runtime, &tab_id)?;
+    runtime.ensure_tab(&tab, surface_size(), ProfileDataMode::Transient, &[], pending_input())?;
+    let latest = current_generation(&runtime, &tab_id)?;
+
+    let mut frames = Vec::new();
+    runtime.collect_responses(
+        &scope(&profile_id),
+        vec![WorkerResponse::Frame {
+            generation: earlier,
+            tab_id: tab_id.as_str().to_string(),
+            frame: live_frame(),
+        }],
+        Instant::now(),
+        &mut frames,
+    );
+
+    assert!(earlier < latest);
+    assert!(matches!(frames.as_slice(), [WebSurfaceRuntimeFrame::Ready { .. }]));
+    Ok(())
+}
+
 #[test]
 fn scope_change_returns_submitted_permission_grants_on_the_next_tick() -> Result<(), String> {
     let mut runtime = WebSurfaceRuntime::new_with_client_factory(empty_client_factory);

crates/ely_app/src/shell/web_surface_runtime_retry_tests.rs

@@ -57,7 +57,9 @@ fn successful_frame_resets_scope_retry_state() {
     let scope = WebSurfaceRuntimeScope::new(ProfileId::new(), ProfileDataMode::Transient);
     let tab_id = TabId::new();
     let generation = RequestGeneration::new(1);
-    session_for_scope(&mut runtime.sessions, &tab_id, scope.clone()).generation = Some(generation);
+    let session = session_for_scope(&mut runtime.sessions, &tab_id, scope.clone());
+    session.generation = Some(generation);
+    session.frame_generation_floor = Some(generation);
     runtime.note_scope_failure(&scope, Instant::now());
     let mut frames = Vec::new();
 

crates/ely_app/src/shell/web_surface_runtime_session.rs

@@ -8,7 +8,7 @@ use crate::services::{
         transient_profile_data_dir,
     },
 };
-use ely_domain::{ProfileId, TabId};
+use ely_domain::{ColorScheme, ProfileId, TabId};
 
 use super::{
     web_surface_cadence::WebSurfacePollCadence,
@@ -42,6 +42,8 @@ pub(super) struct WebSurfaceSession {
     pub(super) scroll_offset: WebSurfaceScrollOffset,
     pub(super) pending_user_navigation: bool,
     pub(super) generation: Option<RequestGeneration>,
+    pub(super) frame_generation_floor: Option<RequestGeneration>,
+    pub(super) color_scheme: Option<ColorScheme>,
     pub(super) cadence: WebSurfacePollCadence,
 }
 
@@ -55,6 +57,8 @@ impl WebSurfaceSession {
             scroll_offset: WebSurfaceScrollOffset::default(),
             pending_user_navigation: false,
             generation: None,
+            frame_generation_floor: None,
+            color_scheme: None,
             cadence: WebSurfacePollCadence::default(),
         }
     }
@@ -64,10 +68,17 @@ impl WebSurfaceSession {
         requested_url: &str,
         size: WebSurfaceSize,
         zoom_percent: u16,
+        color_scheme: ColorScheme,
     ) -> bool {
         self.requested_url != requested_url
             || self.size != size
             || self.zoom_percent != zoom_percent
+            || self.color_scheme != Some(color_scheme)
+    }
+
+    pub(super) fn accepts_frame_generation(&self, generation: RequestGeneration) -> bool {
+        self.frame_generation_floor.is_some_and(|floor| generation >= floor)
+            && self.generation.is_some_and(|latest| generation <= latest)
     }
 
     pub(super) fn url_change_for(