docs(runicnpc): stage 3's design, D239–D242

The org lead answered stage 3's four questions on 2026-09-30:

- D239: a roamer may stand on a player-built floor (Rust's mesh covers it
  a moment after it is built, stage 2), with a warning in the answer.
  §5, §8 and stage 10 now follow it; stage 2's open item is closed.
- D240: routes are recorded point by point (record, point, undo,
  save loop|back, cancel), with nothing drawn on screen.
- D241: placements made in game are named <profile>-<n>, renamable.
- D242: /rnpc place and /rnpc here take key=value options in any order.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

modules/rust/PLAN_REDESIGNS.md

@@ -8,7 +8,7 @@ they can be read together. **Built so far:** §1, walked 2026-09-28 (§1.9); §5
 rig walk still to come (§5.8, D209); §3, built and walked on the rigs and the site 2026-09-29, its in-game
 rows still to come (§3.4); §4, built 2026-09-29 (§4.1). **§6 was spiked on 2026-09-30, and the org lead
 chose neither route: Runic Gateway writes its own NPC plugin, RunicNPC, planned in
-[`../../runicnpc/PLAN.md`](../../runicnpc/PLAN.md) (D214–D238), and the rest of this plan waits for it.**
+[`../../runicnpc/PLAN.md`](../../runicnpc/PLAN.md) (D214–D242), and the rest of this plan waits for it.**
 
 This is a companion to [`PLAN_FIXES.md`](PLAN_FIXES.md) and [`PLAN.md`](PLAN.md). Where they disagree, this
 document is later and wins. Its decisions continue PLAN_FIXES' numbering at **D188**.