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

website/STEAM_SIGNIN.md

@@ -170,4 +170,6 @@ already linked elsewhere refused by core; and, in the browser, both accounts on
 unlinking one, and its Rust link staying (D393).
 
 **Owed:** §6's live walk with a real Steam account and key, on the web and in the app. It needs the org
-lead and joins the end walk's in-game rows.
+lead and joins the end walk's in-game rows, as Parts 1 and 4 of
+[the end walk's in-game pass](../rust-link/PLAYER_WALK.md#the-end-walks-in-game-pass-with-steam-sign-in-plan_redesigns-91-steam_signin-6).
+Module-Rust's core pin moved to the sha website#218 merged as on 2026-10-21 (Module-Rust#53).