fix: invalidate caches inside discuss loop to detect newly written slice context (#1249)

After discussing a slice, the LLM writes S0x-CONTEXT.md. The discuss
loop re-evaluates but hits stale parse caches, showing the slice as
'not discussed' even though the context file exists on disk.

Added invalidateAllCaches() at the top of each loop iteration.

Fixes #1244

src/resources/extensions/gsd/guided-flow.ts

@@ -507,6 +507,9 @@ export async function showDiscuss(
 
   // Loop: show picker, dispatch discuss, repeat until "not_yet"
   while (true) {
+    // Invalidate caches so we pick up CONTEXT files written by the just-completed discussion
+    invalidateAllCaches();
+
     // Build discussion-state map: which slices have CONTEXT files already?
     const discussedMap = new Map<string, boolean>();
     for (const s of pendingSlices) {