codeSplitter conventions: break up the hot one-liners and numbered registries #935

Design: apps/codesplitter/docs/merge-solutions.md, §5. Of the 15 one-liner hunks in #893 and #886, these conventions remove 12 before any merge runs.

• One item per line, with a trailing comma, for objects, types and import lists that grow: DEFAULTS, Settings, Report and Update in deps.ts, the imports in worker.ts, the deps save body in client.html.
• One sentence per line in README.md and REFERENCE.md feature bullets (it renders the same). There are 71 lines over 300 chars today. The doctor bullet is a 6 KB single line.
• Build the doctor's SQL SET, .bind, validator and API body sketch from one field list, so a new setting edits one place instead of six. Two lists coupled by position merge correctly only by luck.
• Timestamped migration names instead of the next number: main's 0069_beams.sql and codeSplitter dependency doctor: rank the packages you care about to settle clashes (#862) #886's 0069_deps_rank.sql merge clean in git, and test/migrations.test.ts fails them.
• Generate features.json (and the REFERENCE file table) from per-feature entries.