refactor(simulation): replace ad-hoc system ordering with TickPhase pipeline (#843)

10-phase linear pipeline: PreInput → Input → Movement → Simulation →
Economy → Storyteller → Snapshot → PostSnapshot → Knowledge → TickAdvance.

Each system assigned to exactly one phase via .in_set(TickPhase::X).
Cross-phase .after()/.before() eliminated — only intra-phase ordering
remains. Prevents schedule cycles by construction.

SimulationPlugin refactored into sub-plugins by domain:
  - InputPlugin (player actions, interactions, dialogue dispatch)
  - MovementPlugin (pathfinding, movement validation, spatial indexing)
  - SocialPlugin (conversations, sound, voice enrichment, follow state)
  - EconomyPlugin (tâtonnement tick, IPC query serving)
  - TimePlugin (chunk streaming, news ticker, tick advancement)

All other plugins (NPC, Knowledge, Perception, Storyteller, Settings,
Bridge) updated to use TickPhase assignments instead of cross-plugin
ordering constraints. BridgePlugin trimmed to bridge I/O concerns only.

Part A of #843. Parts B (multi-threaded executor) and C (background
workers) follow.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/tick_phases.rs

@@ -0,0 +1,71 @@
+//! Server tick cycle — named system set phases (#843).
+//!
+//! Replaces ad-hoc `.after()`/`.before()` constraints with a linear pipeline.
+//! Each system belongs to exactly one phase. Phases execute sequentially.
+//! Within a phase, systems with no intra-phase ordering run in parallel
+//! (when the multi-threaded executor is enabled).
+//!
+//! ```text
+//! PreInput → Input → Movement → Simulation → Economy
+//!     → Storyteller → Snapshot → PostSnapshot → Knowledge → TickAdvance
+//! ```
+//!
+//! ## Rules
+//!
+//! 1. Every system in the Update schedule MUST have `.in_set(TickPhase::X)`.
+//! 2. Cross-phase `.after()`/`.before()` is FORBIDDEN — if you need it,
+//!    the system is in the wrong phase.
+//! 3. Intra-phase `.after()`/`.before()` is allowed for systems within
+//!    the same phase that have a real data dependency.
+
+use bevy_app::prelude::*;
+use bevy_ecs::prelude::*;
+use bevy_ecs::schedule::IntoScheduleConfigs;
+
+/// The 10 phases of the server tick cycle.
+///
+/// Ordered linearly: each phase completes before the next begins.
+/// Configure once in the App with `configure_sets(Update, ...)`.
+#[derive(SystemSet, Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum TickPhase {
+    /// Setup before player input: chunk streaming, bridge input, NPC routine transitions.
+    PreInput,
+    /// Process player actions: input dispatch, door/terminal/examine interactions, dialogue.
+    Input,
+    /// Position resolution: pathfinding, path following, movement validation, spatial indexing.
+    Movement,
+    /// Game logic: NPC behavior, vision, conversations, monologue, sound, visibility geometry.
+    Simulation,
+    /// Economics: tick the economy simulation, serve economy state queries.
+    Economy,
+    /// Storyteller: contamination, activation, tell escalation, tell state derivation.
+    Storyteller,
+    /// Assemble tick output: observer snapshot, ticker, settings, debug commands, save/load.
+    Snapshot,
+    /// React to snapshot: observation events, send to client, anomaly detection.
+    PostSnapshot,
+    /// Update persistent state: knowledge events, cognitive delay, relationships.
+    Knowledge,
+    /// Increment the clock. Must be last.
+    TickAdvance,
+}
+
+impl TickPhase {
+    /// Configure the linear phase ordering on the app.
+    ///
+    /// Call once during plugin setup:
+    /// ```ignore
+    /// TickPhase::configure(&mut app);
+    /// ```
+    pub fn configure(app: &mut bevy_app::App) {
+        use TickPhase::*;
+        app.configure_sets(
+            Update,
+            (
+                PreInput, Input, Movement, Simulation, Economy, Storyteller, Snapshot,
+                PostSnapshot, Knowledge, TickAdvance,
+            )
+                .chain(),
+        );
+    }
+}