feat: complete session preferences and PAM fixture gates

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## Unreleased
+
+- Fixed Wayland compositors launched through user services, including Niri, by
+  providing the selected session type, desktop, seat, and VT to PAM before
+  `pam_open_session`.
+- Session children now receive allowlisted runtime values produced by PAM,
+  including the real logind session ID, runtime directory, and user D-Bus
+  address. Latchd no longer fabricates `XDG_SESSION_ID=latchd`.
+- Extended the disposable PAM fixture to verify both sides of the handoff:
+  selected session metadata entering PAM and PAM-generated values reaching the
+  session child.
+
 ## 0.5.0 — PAM password policy flow
 
 - Added PAM password-change handling for accounts that return
@@ -11,8 +23,12 @@
   current-password/new-password prompt sequence.
 - Added redacted structured audit events for authentication, password changes,
   and session handoff. Raw PAM messages and password material are excluded.
-- Added TUI and core policy-transition tests; the workspace now contains 33
+- Added TUI, core, and preference tests; the workspace now contains 37
   Rust unit tests.
+- Added bounded, atomic last-session preferences per account with owner-only
+  file permissions and a safe fallback when the state file is unavailable.
+- Added disposable PAM deny-policy fault-injection tests. Docker runs them as
+  root; ordinary host runs skip them without touching the host PAM policy.
 
 ## 0.4.0 — Advanced login workflow