feat: update node search result rankings with 2025 usage data (#6939)

Updates the usage data for nodes to improve the search result algorithm.
Old data was from 2024. New data is from Nov 2025 and comes from the
search result interactions only (rather than workflow membership). Old
data is normalized against new data's scale and kept in fields where it
wouldn't have been otherwise overwritten.

Here's a helpful visualization of the before and after for the ranking:
https://www.diffchecker.com/Aa5XTN7F/

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6939-feat-update-node-search-result-rankings-with-2025-usage-data-2b66d73d3650818f9bb5d8765f7f7eaa)
by [Unito](https://www.unito.io)

public/assets/CREDIT.txt

@@ -1 +1,9 @@
-Thanks to OpenArt (https://openart.ai) for providing the sorted-custom-node-map data, captured in September 2024.
+Node usage data merged from two sources:
+- Mixpanel "app:node_search_result_selected" events (Nov 2025): 1,112 nodes, 46,514 selections
+  Reflects actual user search behavior - what users choose when searching.
+- OpenArt workflow data (Sept 2024): 2,600 nodes, 118,676 uses
+  Reflects overall popularity - what's used in workflows.
+
+Merge strategy: New data overwrites old for 514 overlapping nodes. Old data
+normalized by 2.55x scale factor to match new data. Total: 3,198 nodes.
+Search-selected nodes prioritized in ranking.