docs(ui): define web application visual style requirements

PLANS.md

@@ -23,8 +23,10 @@
     not yet available. Expected evidence may be listed in advance.
 11. If later work invalidates recorded evidence, reopen the affected milestone
    and change its status before continuing.
-12. All project documentation, milestone text, source comments, test names, and
-   user-facing diagnostic messages are written in English.
+12. All project documentation, milestone text, source comments, test names,
+    protocol identifiers, and system log messages are written in English.
+    Player-facing browser UI copy, game messages, and browser errors are
+    written in Russian.
 
 ## Milestone 001 — Requirements and technical baseline
 
@@ -397,15 +399,20 @@ into the browser.
 ### Scope
 
 - Name selection, lobby, countdown, running, paused, and result screens.
+- Dark, humorous retro arcade presentation following `docs/UI_STYLE.md`.
+- Russian player-facing copy and locally served pixel-styled graphics.
 - Maze viewport and visual landmarks.
-- Keyboard movement and touchscreen swipes.
+- Keyboard movement, touchscreen swipes, and responsive on-screen arcade
+  controls.
 - Accessible drop-key action.
 - Inventory, vision duration, compass hint, connection, and error feedback.
+- Default sound, supported-device vibration, and animated game feedback.
 - Session restoration after page refresh.
 
 ### Deliverables
 
 - Responsive browser application and compressed production assets.
+- Implemented visual tokens, SVG icon set, and shared control styles.
 - Browser interaction tests for desktop and mobile input.
 - Accessibility and viewport behavior checks.
 
@@ -416,7 +423,17 @@ into the browser.
 3. Hidden and previously seen cells are not retained on screen.
 4. Inventory, effects, hints, pause, and results are unambiguous.
 5. Refresh restores the active player without changing position or inventory.
-6. The production asset image fits its LittleFS partition.
+6. The player flow remains usable without page scrolling at a `412 x 916`
+   CSS-pixel viewport and at representative tablet and desktop viewports.
+7. Player-facing UI copy and browser errors are in Russian while protocol and
+   system-log text remain in English.
+8. The application requires no runtime internet access or third-party UI
+   dependency.
+9. The complete compressed web payload is no larger than 1.5 MiB and fits the
+   unchanged LittleFS partition.
+10. The current stable Chrome, Safari, Firefox, and Edge releases pass the
+    applicable browser interaction checks, with versions and test date
+    recorded in the milestone evidence.
 
 ### Evidence
 
@@ -436,6 +453,7 @@ and reconnect behavior.
 ### Scope
 
 - Full-map observer rendering with player and object updates.
+- Large-screen observer layout with initial full-map fit, zoom, and pan.
 - Observer access without a password and strict read-only authorization.
 - Player disconnect detection and authoritative pause.
 - Session reattachment and 60-second monotonic deadline.
@@ -455,6 +473,8 @@ and reconnect behavior.
 4. Reconnection within 60 seconds restores and resumes the same state.
 5. Reconnection timeout ends the match in a draw.
 6. Observer attempts to send mutation commands are rejected and audited.
+7. Observer mode works at `1024 x 768` CSS pixels and larger, while smaller
+   viewports show the required Russian large-screen message.
 
 ### Evidence