Fix Zoekt filter order to avoid performance regression

Summary

Reorder filters in CodeQueryBuilder so scoping filters (repo_ids, traversal_ids) come immediately after query_string, before meta filters like archived.

Problem

Placing meta filters between query_string and scoping filters causes Zoekt to scan metadata across all repositories before narrowing down, adding ~1-1.4 seconds of latency.

See investigation details in #586416 (comment 3011961678)

Changes

• Reordered filters in build_payload method:
  • Before: query_string → archived → repo_ids/traversal_ids → access_branches
  • After: query_string → repo_ids/traversal_ids → archived → access_branches
• Updated JSON fixtures to match new filter order
• Added specs to verify filter ordering is maintained

Expected Performance Improvements

Search Type	Before	After
Project searches	~1.8s	~200ms
Group searches	~1.7s	~600ms

How to Test

1. Run the specs: bundle exec rspec ee/spec/lib/search/zoekt/code_query_builder_spec.rb
2. All 15 tests should pass, including the new filter ordering tests

Closes #586416 (closed)