fix(workbench): refine agent dock and smooth map resizing

Unify dock surfaces, headers and dividers, and remove the visible context strip.
Limit pointer resizing to 400-640px and reveal the edge grip on hover.
Resize and redraw the map in the same layout cycle to prevent blanking and lag.
Preserve horizontal centering during conversation control press feedback.

Validation: isolated lint, typecheck, 21 focused unit tests, and 10 relevant
browser checks passed. Snapshot baselines regenerated from the isolated change.
The existing mobile alert summary test also fails on unchanged HEAD because
the expected demo alert source is unavailable in this environment.

src/features/workbench/layout/workbench-layout.test.ts

@@ -91,7 +91,7 @@ describe("workbench floating panels", () => {
         agentWidth: 900,
         conditionOpen: false
       }).left
-    ).toBe(744);
+    ).toBe(664);
   });
 
   it("uses responsive defaults and preserves the map corridor at maximum width", () => {
@@ -99,12 +99,14 @@ describe("workbench floating panels", () => {
     expect(getAgentPanelDefaultWidth(1024)).toBe(484);
     expect(getAgentPanelDefaultWidth(1440)).toBe(500);
     expect(getAgentPanelDefaultWidth(1536)).toBe(540);
-    expect(getAgentPanelMaxWidth(1024)).toBe(484);
-    expect(clampAgentPanelWidth(620, 1024)).toBe(484);
+    expect(getAgentPanelMaxWidth(1024)).toBe(500);
+    expect(clampAgentPanelWidth(620, 1024)).toBe(500);
+    expect(clampAgentPanelWidth(300, 1440)).toBe(400);
+    expect(clampAgentPanelWidth(620, 1440)).toBe(620);
     expect(getAgentPanelMaxWidth(1280)).toBe(516);
-    expect(getAgentPanelMaxWidth(1440)).toBe(676);
-    expect(getAgentPanelMaxWidth(1536)).toBe(720);
-    expect(getAgentPanelMaxWidth(1920)).toBe(720);
+    expect(getAgentPanelMaxWidth(1440)).toBe(640);
+    expect(getAgentPanelMaxWidth(1536)).toBe(640);
+    expect(getAgentPanelMaxWidth(1920)).toBe(640);
     expect(getAgentPanelMaxWidth(1920, true)).toBe(628);
   });
 });

src/features/workbench/layout/workbench-layout.ts

@@ -5,7 +5,8 @@ export const WORKBENCH_LAYOUT = {
   wideMinWidth: 1536,
   collapsedAgentWidth: 0,
   collapsedAgentRailWidth: 72,
-  maxAgentWidth: 720,
+  minAgentWidth: 400,
+  maxAgentWidth: 640,
   agentPanelLeftInset: 12,
   conditionPanelRightInset: 64,
   minimumAgentMapCorridor: 256,
@@ -52,10 +53,10 @@ export function clampAgentPanelWidth(
   viewportWidth: number,
   conditionExpanded = false
 ) {
-  const minWidth = getAgentPanelDefaultWidth(viewportWidth, conditionExpanded);
+  const maxWidth = getAgentPanelMaxWidth(viewportWidth, conditionExpanded);
 
   return Math.round(
-    Math.min(Math.max(width, minWidth), getAgentPanelMaxWidth(viewportWidth, conditionExpanded))
+    Math.min(Math.max(width, WORKBENCH_LAYOUT.minAgentWidth), maxWidth)
   );
 }
 
@@ -80,7 +81,6 @@ export function getAgentPanelDefaultWidth(viewportWidth: number, conditionExpand
 export function getAgentPanelMaxWidth(viewportWidth: number, conditionExpanded = false) {
   const layout = getWorkbenchViewportLayout(viewportWidth);
   const conditionWidth = conditionExpanded ? layout.conditionExpandedWidth : layout.conditionWidth;
-  const defaultWidth = getAgentPanelDefaultWidth(viewportWidth, conditionExpanded);
   const widthWithMapCorridor =
     viewportWidth -
     WORKBENCH_LAYOUT.agentPanelLeftInset -
@@ -88,7 +88,7 @@ export function getAgentPanelMaxWidth(viewportWidth: number, conditionExpanded =
     conditionWidth -
     WORKBENCH_LAYOUT.minimumAgentMapCorridor;
 
-  return Math.max(defaultWidth, Math.min(WORKBENCH_LAYOUT.maxAgentWidth, widthWithMapCorridor));
+  return Math.min(WORKBENCH_LAYOUT.maxAgentWidth, Math.max(layout.agentWidth, widthWithMapCorridor));
 }
 
 export type WorkbenchPanelState = {