fix(workspace): restore View button functionality and clean up dead props

Fix two issues identified in code review:

1. Critical: onViewFromHistory was a silent no-op. Now navigates to the
   SessionDetail page using the same route pattern as the external link in
   RunHistory, allowing users to view a finished run's transcript.

2. Important: Removed dead slashCommands={[]} prop from RunSetup invocation.
   Made slashCommands optional in RunSetupProps to maintain type safety while
   reflecting that the discovery logic was removed.

All tests pass (396 client, 1152 server).

client/src/components/run/RunSetup.tsx

@@ -112,7 +112,7 @@ interface RunSetupProps {
    *  sessions. Undefined when no lane is selected (the picker then lists
    *  everything, same as before lanes existed). */
   laneCwd?: string;
-  slashCommands: SlashCommand[];
+  slashCommands?: SlashCommand[];
   runHistory: DashboardRunHistoryItem[];
   onResumeFromHistory: (item: DashboardRunHistoryItem) => void;
 }
@@ -172,7 +172,7 @@ export function RunSetup(props: RunSetupProps) {
           onSubmit={() => handleStart(props)}
           placeholder={t("fields.promptPlaceholderTerminal")}
           rows={5}
-          slashCommands={props.slashCommands}
+          slashCommands={props.slashCommands ?? []}
           fileCwd={props.resumeSession?.cwd || props.cwd}
         />
         <div className="mt-1 text-[10px] text-fg-muted">

client/src/pages/Workspace.tsx

@@ -38,7 +38,7 @@
  * ----------------------------------------------------------------------------- */
 
 import { useCallback, useEffect, useRef, useState, useSyncExternalStore } from "react";
-import { useSearchParams } from "react-router-dom";
+import { useSearchParams, useNavigate } from "react-router-dom";
 import { useTranslation } from "react-i18next";
 import { Play, AlertCircle, X, Plus } from "lucide-react";
 import { api } from "../lib/api";
@@ -307,12 +307,16 @@ export function Workspace() {
     [busy, refreshList, t, lanes]
   );
 
-  // View a past run inline: not implemented in the new TerminalView architecture.
-  // The old RunConsole showed transcripts inline, but TerminalView only shows live
-  // runs. Use SessionDetail page instead.
-  const onViewFromHistory = useCallback(() => {
-    // No-op: feature moved to SessionDetail page
-  }, []);
+  // View a past run: navigate to the SessionDetail page which shows the transcript.
+  const navigate = useNavigate();
+  const onViewFromHistory = useCallback(
+    (item: DashboardRunHistoryItem) => {
+      if (item.session_id) {
+        navigate(`/sessions/${encodeURIComponent(item.session_id)}`);
+      }
+    },
+    [navigate]
+  );
 
   const start = useCallback(async () => {
     if (!prompt.trim() || busy) return;
@@ -802,7 +806,6 @@ export function Workspace() {
             laneCwd={currentLane?.cwd}
             resumeSession={resumeSession}
             onResumeSessionChange={setResumeSession}
-            slashCommands={[]}
             runHistory={runHistory}
             onResumeFromHistory={onResumeFromHistory}
           />