Fix Manage Kits for apps read from a device

The schema built from a Sox session spelled checksums as signed decimals,
so no kit matched a manifest: Installed showed raw checksums and Action
read "Keep at checksum ...". They are now 8 hex digits like a .sax file,
and checksums compare regardless of zero-padding.

A device session only loads folders as they are opened, so only sys
counted as used. Used kits now come from the whole component tree, read
one request at a time so a small controller is not flooded into dropping
the session.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

device_session.py

@@ -176,6 +176,41 @@ class DeviceSession:
                 for cid in parent.children
                 if self.sox_client.cache_get(cid) is not None]
 
+    def used_kit_names(self):
+        """Every kit a component on the device belongs to, loading the whole tree to see.
+
+        The DOM only holds what has been opened, so it cannot answer this on its own. Only
+        the tree is read — no config or runtime.
+
+        Requests go one at a time. A small controller handles a single folder's burst fine,
+        but a back-to-back stream of them fills its receive buffer; it stops acking, and
+        DASP closes the whole session ("unacked send timeout"). Waiting for each reply
+        before sending the next keeps it at the pace the device sets. Anything already
+        cached costs nothing, so only the first call is slow.
+        """
+        client = self.sox_client
+        if client is None:
+            return set()
+
+        pending = [0]
+        loaded = 0
+        while pending:
+            comp_id = pending.pop()
+            comp = client.cache_get(comp_id)
+            if comp is None:
+                comp = client.load_ids([comp_id], checked=False)[0]
+                loaded += 1
+                if loaded % 20 == 0:
+                    app_state.set_status(f"Reading components from the device… {loaded}")
+                    if app_state.status_label is not None:
+                        app_state.status_label.update_idletasks()
+            if comp is not None:
+                pending.extend(comp.children)
+
+        parts = client.schema_parts or []
+        return {parts[c.kit_id].name for c in client.cache
+                if c is not None and 0 <= c.kit_id < len(parts)}
+
     def find_component_of_type(self, type_name, slot_name):
         """A component of `type_name` with `slot_name` read, loading where services live.
 
@@ -294,8 +329,10 @@ class DeviceSession:
         schema_elem = ET.SubElement(sax_root, "schema")
         if self.sox_client and self.sox_client.schema_parts:
             for part in self.sox_client.schema_parts:
+                # Sox sends the checksum as a signed int; .sax files and manifest names
+                # spell it as 8 hex digits, and nothing matches unless this does too.
                 ET.SubElement(schema_elem, "kit",
-                              name=part.name, checksum=str(part.checksum))
+                              name=part.name, checksum=f"{part.checksum & 0xFFFFFFFF:08x}")
 
         app_elem = ET.SubElement(sax_root, "app")
         if root_comp is not None: