batch3 T8: chat->file click, Session.tsx rewires to Workspace, sidebar polish

- MessageBubble & ToolCallCard: detect path-like strings in rendered text
  via regex requiring slash+extension; clicks dispatch open_file_in_browser
- Session.tsx: now renders <Workspace sessionId projectId>; on mount,
  emits session_loaded so sidebar can highlight even deep-linked sessions
  not in the recent_sessions cache
- ProjectSidebar: active project's chevron visually disabled (50% opacity,
  cursor-not-allowed) and click no-op; activeSession from useSidebar used
  as fallback when active session isn't in cache

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/components/ToolCallCard.tsx

@@ -1,12 +1,50 @@
 import { useState } from 'react';
+import type { ReactNode } from 'react';
 import { ChevronRight, Wrench } from 'lucide-react';
 import type { Message, ToolCall } from '@/api/types';
+import { sessionEvents } from '@/hooks/sessionEvents';
 
 interface Props {
   message?: Message;
   toolCall?: ToolCall;
 }
 
+// Same regex/heuristic as MessageBubble: paths ending in `.ext` with at
+// least one `/`. Linkifies file paths emitted by tools like grep / find_files
+// so they're clickable.
+const PATH_REGEX = /([a-zA-Z0-9._/-]+\.[a-zA-Z0-9]+)/g;
+
+function linkifyOutput(text: string): ReactNode[] {
+  const out: ReactNode[] = [];
+  let lastIdx = 0;
+  let idx = 0;
+  for (const match of text.matchAll(PATH_REGEX)) {
+    const matchedText = match[0];
+    const start = match.index ?? 0;
+    if (!matchedText.includes('/')) continue;
+    if (start > lastIdx) out.push(text.slice(lastIdx, start));
+    out.push(
+      <button
+        key={idx}
+        type="button"
+        onClick={() =>
+          sessionEvents.emit({
+            type: 'open_file_in_browser',
+            path: matchedText,
+          })
+        }
+        className="text-primary underline cursor-pointer hover:text-primary/80"
+      >
+        {matchedText}
+      </button>
+    );
+    lastIdx = start + matchedText.length;
+    idx += 1;
+  }
+  if (lastIdx < text.length) out.push(text.slice(lastIdx));
+  return out.length > 0 ? out : [text];
+}
+
 export function ToolCallCard({ message, toolCall }: Props) {
   const [open, setOpen] = useState(false);
   const tc = toolCall ?? message?.tool_calls?.[0];
@@ -48,7 +86,11 @@ export function ToolCallCard({ message, toolCall }: Props) {
             </pre>
           ) : output !== undefined ? (
             <pre className="text-xs font-mono whitespace-pre-wrap overflow-x-auto max-h-72 overflow-y-auto">
-              {typeof output === 'string' ? output : JSON.stringify(output, null, 2)}
+              {linkifyOutput(
+                typeof output === 'string'
+                  ? output
+                  : JSON.stringify(output, null, 2)
+              )}
             </pre>
           ) : (
             <div className="text-xs text-muted-foreground">no result yet</div>