Added selective dump features

app/composables/useFrames.ts

@@ -1,16 +1,8 @@
 import { ref, computed, shallowRef } from 'vue'
 import { emptyView, sameView, type ViewState } from '../lib/view-state'
 
-/**
- * The filter history: a queue of frames plus a cursor into it.
- *
- * This is deliberately the app's own history rather than the browser's.
- * Browser history cannot be truncated — pushing after going back leaves the
- * forward entries reachable by gesture — and it is shared with whatever the
- * user did before arriving here, so "back" would eventually walk off the
- * site mid-investigation. Owning the queue means the URL can be rewritten in
- * place (replaceState) and still be exactly as linkable.
- */
+export const FRAME_LIMIT = 50
+
 export function useFrames() {
   const frames = shallowRef<ViewState[]>([emptyView()])
   const index = ref(0)
@@ -19,25 +11,20 @@ export function useFrames() {
   const canBack = computed(() => index.value > 0)
   const canForward = computed(() => index.value < frames.value.length - 1)
 
-  /**
-   * Record a frame. A change made from anywhere but the newest frame discards
-   * everything after the cursor first: the user has branched, and the frames
-   * they walked back past are no longer reachable from where they now are.
-   *
-   * The equality check is what makes replay safe. Stepping back sets the
-   * filter refs to the frame at the cursor, which re-triggers the watchers
-   * that call this — and a frame identical to the current one is dropped, so
-   * no flag is needed to tell a replay from a real change.
-   */
   function push(v: ViewState) {
     if (sameView(v, current.value)) return
     const kept = frames.value.slice(0, index.value + 1)
     kept.push(v)
-    frames.value = kept
-    index.value = kept.length - 1
+
+    frames.value = kept.length > FRAME_LIMIT ? kept.slice(kept.length - FRAME_LIMIT) : kept
+    index.value = frames.value.length - 1
+  }
+
+  function clear() {
+    frames.value = [current.value]
+    index.value = 0
   }
 
-  /** Drop the whole queue — used when a different dump is opened. */
   function reset(v: ViewState = emptyView()) {
     frames.value = [v]
     index.value = 0
@@ -57,6 +44,7 @@ export function useFrames() {
     canBack,
     canForward,
     push,
+    clear,
     reset,
     back: () => go(-1),
     forward: () => go(1),