Trim dead code and tighten the branch to surgical scope

- palette-picker.js: drop the superseded APP/DOCS/INDEX copy tables, the
  disabled font-rail hoist machinery, LOREM.caption, and an orphan marker
- design-context.css + dcx-hierarchy.css: drop the demo-era specimen,
  radius, and spacing-bar rule groups nothing renders
- index.astro: drop an unreferenced boards const
- de-export module-internal names (store, bindings, portability,
  visual-cues); remove picker-server's unused doc-session kill switch and
  document --doc in its help
- palette.mjs: realpath the entry guard so symlinked installs still run
  the CLI (same guard as visual-cues.mjs)
- revert serve-question.mjs copy ride-along; drop the plan/ gitignore
  entry; dedupe a build-picker comment; file design-context with the
  system category entries; alphabetize IMPECCABLE_SUB_COMMANDS
- new-work.md: drop a same-screen restatement of the comp/world ranking
- CLAUDE.md: correct the picker gate baseline to the measured 606 and
  explain the per-element multiplication; the trims removed the two
  dead-block font findings
- DESIGN-CONTEXT-ARCHITECTURE.md: list portability.mjs in the code layout

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/DESIGN-CONTEXT-ARCHITECTURE.md

@@ -77,6 +77,7 @@ skill/scripts/design-context/
   store.mjs            the only code that knows store paths or writes store files
   bindings.mjs         the editable-field registry for the document
   session-routes.mjs   HTTP handlers for the document edit session
+  portability.mjs      the export bundle format and its import validation
 
 skill/scripts/
   picker-server.mjs      static serving, boot contract, submit, autosave, spawn