Reduce codebase by implementing top five refactoring

Identify top 5 opportunities to massively reduce the amount of code (lines of code) in any part of the repo: - Similar functionality that can be unified and reused - Code that has been valuable but no more - A front end component or a group of them duplicate another component/page functionality. Use the most modern and nice looking - etc. Now implement them :)

Shipped the five reductions a lean tree still allows (net −473 lines, 114 files, PR #6907 queued to the merge lane): API test fixtures single-homed in conftest (82 modules); Change-org frame + PrincipalMultiSelect on useAsyncOptions; three lists onto FeedList; censuses on census_ast, flush_or_409, two orphan gates wired; port-grid primitives from worktree_mechanics/ports. Recon found no dead code anywhere; the thousands-of-lines cuts (NodeLink v1 wire, older-daemon compat, D5 aliases, legacy redirects, worktree-agents, OpenAPI types) each need a named decision and are deferred in the report. Quick gate, changed-area tests (3,927 API + 11,886 web), review, security and verifier lanes green; visual check on NodeLink/Storage lists, ledger, Change-org and Add-access dialogs at 1280 and 390px done and readable. Memory: used mem-25288; proposed none.