ui/phase-25: backend turn-cutoff guard + auto-pause + UI sync protocol

Backend now owns the turn-cutoff and pause guards the order tab
relies on: the scheduler flips runtime_status between
generation_in_progress and running around every engine tick, a
failed tick auto-pauses the game through OnRuntimeSnapshot, and a
new game.paused notification kind fans out alongside
game.turn.ready. The user-games handlers reject submits with
HTTP 409 turn_already_closed or game_paused depending on the
runtime state.

UI delegates auto-sync to a new OrderQueue: offline detection,
single retry on reconnect, conflict / paused classification.
OrderDraftStore surfaces conflictBanner / pausedBanner runes,
clears them on local mutation or on a game.turn.ready push via
resetForNewTurn. The order tab renders the matching banners and
the new conflict per-row badge; i18n bundles cover en + ru.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/openapi.yaml

@@ -2314,9 +2314,10 @@ components:
           type: string
           description: |
             Stable machine-readable failure marker. The closed set is
-            `not_implemented`, `invalid_request`, `unauthorized`, `not_found`,
-            `conflict`, `method_not_allowed`, `internal_error`,
-            `service_unavailable`.
+            `not_implemented`, `invalid_request`, `unauthorized`,
+            `forbidden`, `not_found`, `conflict`, `method_not_allowed`,
+            `internal_error`, `service_unavailable`,
+            `turn_already_closed`, `game_paused`.
           enum:
             - not_implemented
             - invalid_request
@@ -2327,6 +2328,8 @@ components:
             - method_not_allowed
             - internal_error
             - service_unavailable
+            - turn_already_closed
+            - game_paused
         message:
           type: string
           description: Human-readable client-safe failure description.