fix(session): reset lobby when player leaves finished match

PLANS.md

@@ -3443,8 +3443,9 @@ resources.
 Let an authenticated player or observer deliberately leave through the
 top-right settings menu, revoke only that browser's session, immediately free
 its slot, and return it to the name-entry screen with its previous display name
-prefilled. A player leaving an unfinished match must authoritatively cancel
-that match and return every remaining participant to the lobby, while an
+prefilled. A player leaving any non-waiting match phase, including a finished
+result, must authoritatively cancel that match and return every remaining
+participant to the lobby, while an
 observer departure or a lobby departure must not reset gameplay.
 
 ### Scope
@@ -3457,10 +3458,10 @@ observer departure or a lobby departure must not reset gameplay.
   authenticated player or observer session; do not show it on the unauthenticated
   welcome and name-entry screen.
 - Require a modal confirmation before sending an exit command. For a player in
-  countdown, active, finish-pending, or paused state, clearly warn that the
-  current match will end for everyone and the player's slot will be freed. For
-  a player in the lobby or an observer in any phase, explain that only this
-  browser's place will be released.
+  countdown, active, finish-pending, paused, or finished state, clearly warn
+  that the current match will return everyone to the waiting lobby and the
+  player's slot will be freed. For a player in the lobby or an observer in any
+  phase, explain that only this browser's place will be released.
 - Treat opening or cancelling the confirmation as browser-local UI only. While
   it is open, suppress input from that browser without pausing or otherwise
   mutating authoritative state; cancelling must restore the previous screen,
@@ -3469,15 +3470,14 @@ observer departure or a lobby departure must not reset gameplay.
   correlated success response. It must be distinct from an unexpected socket
   disconnect, page reload, or transient connection loss, which retain the
   existing 60-second player reconnection contract.
-- On an accepted player leave during countdown, active, finish-pending, or
-  paused state, stop all match timers, clear the current authoritative match,
-  return the lobby to its waiting state, retain every other connected session
-  and role, revoke the leaving session, free its player slot immediately, and
-  broadcast the cancellation and fresh lobby state to the remaining players
-  and observers.
-- On an accepted player leave while already in the waiting lobby or after a
-  completed result, revoke only that player's session and free its slot. Do not
-  reset an unfinished match because none is active in those phases.
+- On an accepted player leave during countdown, active, finish-pending, paused,
+  or finished state, stop all match timers, clear the current authoritative
+  match, return the lobby to its waiting state, retain every other connected
+  session and role, revoke the leaving session, free its player slot
+  immediately, and broadcast the cancellation and fresh lobby state to the
+  remaining players and observers.
+- On an accepted player leave while already in the waiting lobby, revoke only
+  that player's session and free its slot.
 - On an accepted observer leave in any phase, revoke only that observer's
   session and free its observer slot. Never pause, reset, finish, restart, or
   otherwise mutate the match because an observer leaves.
@@ -3536,18 +3536,20 @@ observer departure or a lobby departure must not reset gameplay.
    modal and sends no protocol command until explicit confirmation. Cancelling,
    pressing Escape, or activating the modal's cancel action leaves the session
    and authoritative state unchanged and safely restores focus.
-3. A player confirmation during countdown, active, finish-pending, or paused
-   state explicitly says that the match will end for everyone and the slot will
-   be freed. Confirmation produces exactly one authoritative cancellation,
-   stops every relevant timer, clears the current match, and returns all
-   remaining connected participants to a fresh waiting lobby.
+3. A player confirmation during countdown, active, finish-pending, paused, or
+   finished state explicitly says that the match will return everyone to the
+   waiting lobby and the slot will be freed. Confirmation produces exactly one
+   authoritative cancellation, stops every relevant timer, clears the current
+   match, and returns all remaining connected participants to a fresh waiting
+   lobby.
 4. The leaving player's session is removed and its slot becomes available in
    the same accepted server transition. Every other player's and observer's
    session, role, and connection remain valid, and the resulting lobby snapshot
    consistently shows the newly free slot.
-5. A player leaving the waiting lobby or a completed result releases only that
-   player's session and slot. It does not disconnect other participants or
-   perform an additional match reset.
+5. A player leaving the waiting lobby releases only that player's session and
+   slot. A player leaving a completed result performs the same authoritative
+   return-to-lobby transition as another non-waiting player exit, without
+   disconnecting any remaining participant.
 6. An observer leaving during any phase releases only that observer session and
    observer slot. Match phase, players, timers, maze, objects, inventory, and
    results remain byte-for-byte unchanged except for the expected lobby
@@ -3586,11 +3588,12 @@ observer departure or a lobby departure must not reset gameplay.
 15. All host and browser tests pass; compressed-web-asset validation passes;
     the payload remains within the 1.5 MiB web budget and LittleFS partition;
     and firmware remains within the factory partition.
-16. Physical-device testing confirms that a player can cancel an unfinished
-    match and immediately release its slot, an observer can leave without
-    affecting play, the remaining browsers receive the correct lobby state,
-    and the departing browser returns to a prefilled name-entry screen without
-    stale controls, delayed input, or reconnect side effects.
+16. Physical-device testing confirms that a player can cancel a non-waiting
+    match, including a finished result, and immediately release its slot, an
+    observer can leave without affecting play, the remaining browsers receive
+    the correct lobby state, and the departing browser returns to a prefilled
+    name-entry screen without stale controls, delayed input, or reconnect side
+    effects.
 17. The project owner confirms on representative mobile and desktop browsers
     that the exit action is easy to find but difficult to trigger accidentally,
     its consequences are clear, and all role-specific outcomes match the
@@ -3614,3 +3617,30 @@ observer departure or a lobby departure must not reset gameplay.
   immediate server-side session revocation, player-match cancellation, and a
   browser confirmation flow that clears the temporary token only after the
   correlated acknowledgement.
+- On 2026-09-13, a corrective lifecycle inspection found that the explicit
+  player-leave handler excluded `MAZE32_GAME_PHASE_FINISHED` from its match
+  reset condition. It therefore revoked the departing result-screen session
+  but did not broadcast `reset`, which could leave remaining clients behind an
+  unusable result modal. The handler now resets for a player leaving every
+  non-waiting lobby phase, including a completed result; it keeps waiting-lobby
+  player exits and observer exits session-scoped. The reset is broadcast before
+  the fresh lobby snapshot, and browser reset handling hides the modal and
+  renders the waiting lobby.
+- On 2026-09-13, `node --test test/web/test_player_app.js` passed 31 tests,
+  including the result-phase leave regression that verifies the confirmation
+  warning, server reset condition, correlated token cleanup, modal dismissal,
+  and lobby rendering. `bash scripts/run_host_tests.sh` passed all suites;
+  its lobby/protocol suite reported explicit leave session revocation and slot
+  reuse as passing, including invalid-token restoration after either Player 1
+  or Player 2 leaves, retained player and observer sessions, observer-only
+  leave, duplicate leave idempotence, and immediate replacement of both player
+  slots. `python3
+  scripts/verify_web_assets.py` passed with deterministic payload
+  `3fb28e1ae55deba0ac592bcd99d81b7e95271604a5b35d7f293c4b8bffef6143` at
+  33,183 / 1,572,864 bytes. `/home/sasa/.platformio/penv/bin/pio run` passed
+  at 1,030,256 / 2,097,152 factory bytes, and `/home/sasa/.platformio/penv/bin/pio
+  run --target buildfs` passed at 2,031,616 / 2,031,616 LittleFS bytes.
+- On 2026-09-13, the project owner checked the corrected result-screen exit
+  flow in the browser and confirmed that the issue was fixed: a remaining
+  participant is returned from the result modal to a usable waiting lobby when
+  the other player explicitly leaves.