docs(rust): plan the end walk's in-game pass, with Steam sign-in

PLAYER_WALK.md gains one section covering every row still owed after the
end walk's four passes (PLAN_REDESIGNS §9.1), plus Steam sign-in's live
walk (STEAM_SIGNIN §6). Steam comes first because linking A's Steam
account is also what makes A a linked Rust player (D392) for the reward
rows. Rows that already passed are left out. B-only rows and the phone
are split into their own parts, and AutoDoors 3.3.12 replaces
NightVision as the perk plugin.

PLAN_REDESIGNS §9.1 and STEAM_SIGNIN §8 point to the new section.
STEAM_SIGNIN §8 also records Module-Rust#53, the core pin moved to
#218's merge.

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

modules/rust/PLAN_REDESIGNS.md

@@ -1046,7 +1046,10 @@ permission lend landing for a player who has joined it; §12.9's and D333's mess
 permission already held kept; a reward by command online, to a name with spaces and a quote; a Dangerous Treasures
 chest won, a Guarded Crate cleared, ZLevels' rate moving with `vip2`; whether a hand revive (hold E) counts as a
 heal; and PLAN_FIXES §8's tail — the Carbon rows of the first player walk nothing has covered since, its row 8 and
-the map walk with a second player, events step 7 with several players, and the phone walk.
+the map walk with a second player, events step 7 with several players, and the phone walk. **These rows, with
+Steam sign-in's live walk ahead of them, are planned as one pass in
+[`PLAYER_WALK.md`](../../rust-link/PLAYER_WALK.md#the-end-walks-in-game-pass-with-steam-sign-in-plan_redesigns-91-steam_signin-6)
+(2026-10-21).**
 
 ## 10. Decisions of record