feat(simulation): add ObserverSnapshot v2 schema with visibility types (#358, #25)

Expand wire protocol with version field, GameTime (day/phase/paused),
FacingDirection (8-directional), VisibleTile, VisibilitySector
(Forward/Peripheral), and visibility tag on VisibleEntity.
Regenerate all msgpack fixtures for client compatibility.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/bridge/types.rs

@@ -1,21 +1,86 @@
-// Bridge type definitions
-// ObserverSnapshot: data crossing the client-server boundary
+// Bridge type definitions — v2 (Sprint 2: See)
+// ObserverSnapshot: data crossing the client-server boundary (D-020)
 // PlayerInput: semantic actions from client
 
 use bevy_ecs::prelude::*;
 use serde::{Deserialize, Serialize};
 
+pub use crate::simulation::time::DayPhase;
+
 /// The ONLY data structure crossing the client-server boundary (D-020)
 /// Contains all information visible to the observer at a given tick.
 ///
-/// TODO: Planned fields — fog/visibility data, ambient sound events,
-/// internal monologue triggers, HUD state (D-020 expansion).
+/// v2 adds: game_time, player_facing, visible_tiles, visibility sectors.
+/// Future fields: ambient sound events, internal monologue triggers,
+/// HUD state (D-020 expansion).
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ObserverSnapshot {
+    /// Protocol version for forward compatibility. Current: 2.
+    pub version: u8,
     /// Simulation tick when this snapshot was produced
     pub tick: u64,
-    /// All entities visible to the observer
+    /// Game time data for client HUD display (D-031)
+    pub game_time: GameTime,
+    /// Player character's facing direction for vision cone (D-015)
+    pub player_facing: FacingDirection,
+    /// All entities visible to the observer (filtered by LOS + vision cone)
     pub entities: Vec<VisibleEntity>,
+    /// Tiles visible to the observer for fog rendering
+    pub visible_tiles: Vec<VisibleTile>,
+}
+
+/// Game time data for client display (D-031)
+/// 10 ticks = 1 game-minute, 4 day phases of 360 minutes each.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct GameTime {
+    /// Current day (0-indexed)
+    pub day: u64,
+    /// Time of day in game-minutes (0..1439)
+    pub time_of_day: u64,
+    /// Current day phase (Morning/Afternoon/Evening/Night)
+    pub day_phase: DayPhase,
+    /// Whether simulation is paused
+    pub paused: bool,
+}
+
+/// 8-directional facing direction, matching movement system.
+/// Used for vision cone computation (D-015) and snapshot wire format.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum FacingDirection {
+    North,
+    Northeast,
+    East,
+    Southeast,
+    South,
+    Southwest,
+    West,
+    Northwest,
+}
+
+impl Default for FacingDirection {
+    fn default() -> Self {
+        FacingDirection::North
+    }
+}
+
+/// A tile visible to the observer with its visibility quality
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct VisibleTile {
+    pub x: i32,
+    pub y: i32,
+    pub z: i32,
+    /// Which vision cone sector this tile falls in (D-015)
+    pub visibility: VisibilitySector,
+}
+
+/// Vision cone sectors per D-015.
+/// Behind = not visible at all (tile absent from visible_tiles list).
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum VisibilitySector {
+    /// Full LOS, full detail (forward arc)
+    Forward,
+    /// Reduced range, dimmer rendering (side arcs)
+    Peripheral,
 }
 
 /// A visible entity in the simulation
@@ -28,10 +93,12 @@ pub struct VisibleEntity {
     pub y: f32,
     pub z: i32,
     pub kind: EntityKind,
+    /// Which vision cone sector this entity falls in (D-015)
+    pub visibility: VisibilitySector,
 }
 
 /// Category of visible entity
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 pub enum EntityKind {
     Player,
     Npc,