feat(simulation): generation pipeline Rust types + SystemNameIndex (#900, #912-#926)

WorldTier enum fixed to Epicenter/Regional/Backwater/Passage/Waypoint
(D-218). Full enum implementations for ComplexityTier, SettingType,
SettlementClass, DistrictType, PoliticalArchetype, FoundingOrientation,
TerritorialStatus, GeographicAttractor, AttractorType, and
CompatibilityMatrix. SystemNameIndex with Aho-Corasick text scanning
for background pre-generation queue integration (D-206).

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

server/src/simulation/generator.rs

@@ -100,15 +100,19 @@ pub type PlacedObject = String;
 /// Network importance of a world in the galaxy.
 /// Determines simulation fidelity budget and NPC complexity ceiling.
 ///
-/// Source: tyre-round4.md §2.1, workshop-outcomes.md
+/// Source: D-218, workshop-outcomes.md
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum WorldTier {
-    /// Background system — minimal simulation, sparse NPCs. Pure environmental.
-    Peripheral,
-    /// Standard Settled Reach system — full simulation, complex social sites.
-    Connected,
-    /// Major hub — maximum fidelity, multi-faction politics, all triangle types.
-    Core,
+    /// Hub system. Full simulation, high faction pressure.
+    Epicenter,
+    /// Regional system. 1–4 districts, partial full-budget simulation.
+    Regional,
+    /// Small community. 1 district. Network-insignificant, NOT budget-capped.
+    Backwater,
+    /// Transit stop. Pass-through node. Moderate complexity ceiling.
+    Passage,
+    /// Not simulated until player approaches. Minimal complexity ceiling.
+    Waypoint,
 }
 
 /// Generator content budget for a district.
@@ -288,6 +292,147 @@ pub enum EraCause {
     CulturalShift,
 }
 
+// ---------------------------------------------------------------------------
+// Settlement classification enums (D-196, D-212, D-213, D-214, D-215)
+// ---------------------------------------------------------------------------
+
+/// How a settlement enters and exits active simulation.
+/// Controls whether generation runs, and at what complexity level.
+/// Source: D-196
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
+pub enum SettlementClass {
+    /// Named in wiki; always active regardless of population threshold.
+    NameLocked,
+    /// Active if pop ≥ 50_000; ghost stub if pop < 5_000.
+    PopulationBudget,
+    /// Active only while the triggering economic condition holds.
+    EconomicTriggered,
+    /// Emergent settlement not in atlas at generation time; written during simulation.
+    OrganicGrowth,
+}
+
+/// Dominant power structure of a settlement and its physical spatial expression.
+/// Derived from TerritorialStatus + economic_role at generation time.
+/// Source: D-214
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
+pub enum PoliticalArchetype {
+    /// Top-down Commission planning; rectilinear, institutional core, radial-core arrangement.
+    Commission,
+    /// Corp-dominated; commercial density, restricted campus blocks, restricted-perimeter adjacent.
+    Corporate,
+    /// Self-organized; organic growth, mixed use, ribbon arrangement.
+    Pioneer,
+    /// Garrison or fortification origin; defensible geometry, fortified-perimeter arrangement.
+    Military,
+    /// University or research origin; campus-quad structure, green space, radial-core arrangement.
+    Academic,
+    /// Factory-first; large-footprint industrial blocks, worker residential rings, ribbon arrangement.
+    Industrial,
+}
+
+/// Primary spatial axis of a city's original street grid.
+/// Derived from the matched attractor type (D-211). Controls district grid rotation.
+/// Source: D-213
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub enum FoundingOrientation {
+    /// Street grid perpendicular to coastline. `facing_degrees`: compass bearing toward water (0–359).
+    Coastal { facing_degrees: u16 },
+    /// Street grid parallel to founding river. `bearing_degrees`: river flow direction (0–359).
+    RiverAligned { bearing_degrees: u16 },
+    /// Grid rotated to follow local contours (valley floor settlements).
+    TerrainFollowing,
+    /// Grid aligned to cardinal N/S/E/W (Commission-planned settlements on flat terrain).
+    Cardinal,
+    /// Arbitrary bearing (pioneer settlements on open terrain). `bearing_degrees`: 0–359.
+    Free { bearing_degrees: u16 },
+}
+
+/// Territory control status for a province (drainage basin). Priority-ordered derivation.
+/// Source: D-212
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
+pub enum TerritorialStatus {
+    /// Commission faction_influence ≥ 0.6 in this province.
+    CommissionControlled,
+    /// Single corporation faction_influence ≥ 0.5.
+    CorpTerritory,
+    /// Two or more factions each ≥ 0.3; no dominant faction.
+    ContestedZone,
+    /// No faction with influence ≥ 0.2.
+    FrontierUnclaimed,
+    /// Cultural corridor has indigenous autonomy flag.
+    IndigenousHeld,
+    /// Population density < 0.01 AND no faction ≥ 0.1.
+    Derelict,
+}
+
+// ---------------------------------------------------------------------------
+// Attractor types for settlement placement (D-195, D-209, D-211)
+// ---------------------------------------------------------------------------
+
+/// The type of terrain feature that attracts settlement placement.
+/// Source: D-195, D-209
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
+pub enum AttractorType {
+    /// Where a river meets sea level or coastline. Historically high-value.
+    RiverMouth,
+    /// Proximity to coast without a river mouth. Port access.
+    CoastalAccess,
+    /// Where a river crosses a topographic saddle or confluence point.
+    RiverCrossing,
+    /// Local elevation minimum; flat, arable, sheltered.
+    ValleyFloor,
+    /// Saddle point between adjacent drainage basins; controls a mountain pass.
+    PassEntrance,
+    /// Adjacent to a lake polygon.
+    LakeShore,
+    /// Flat terrain away from all other attractors; fallback for plains settlements.
+    PlainCenter,
+}
+
+/// A terrain feature at a specific map position that influences city placement scoring.
+/// Source: D-195, D-209
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct GeographicAttractor {
+    /// Pixel position in heightmap space [row, col].
+    pub position: (u16, u16),
+    pub attractor_type: AttractorType,
+    /// Normalized strength 0.0–1.0. Derived from flow accumulation or habitability score.
+    pub strength: f32,
+}
+
+/// Compatibility weights between economic roles and attractor types.
+/// A 10×7 matrix (10 economic_role values × 7 AttractorType variants).
+/// Each cell is a weight multiplier 0.0–3.0 applied during attractor-matching scoring.
+/// Source: D-195
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct CompatibilityMatrix {
+    /// Row order: manufacturing, financial, agricultural, extraction, service_mixed,
+    ///   institutional, transit_hub, research, military, residential.
+    /// Column order: RiverMouth, CoastalAccess, RiverCrossing, ValleyFloor,
+    ///   PassEntrance, LakeShore, PlainCenter.
+    pub weights: [[f32; 7]; 10],
+}
+
+/// Data contract between build-time (systems.db) and the runtime-background
+/// generation tier. Populated from atlas_city_names + bodies at generation
+/// dispatch time. All 8 fields are required before a generation task may run.
+/// Source: D-200, D-199
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct CityGenerationContext {
+    /// Foreign key into atlas_city_names.id
+    pub city_id: u64,
+    pub political_archetype: PoliticalArchetype,
+    /// Starting economic health seed (0.0–1.0). Derived per D-197.
+    pub prosperity_baseline: f32,
+    pub surrounding_biome: SettingType,
+    /// Compass octants (0=N, 1=NE … 7=NW) where roads enter the city footprint.
+    pub road_entry_directions: Vec<u8>,
+    /// City footprint radius in km. Derived from body_radius_km (D-204) + population.
+    pub footprint_radius_km: f32,
+    pub founding_orientation: FoundingOrientation,
+    pub world_tier: WorldTier,
+}
+
 // ---------------------------------------------------------------------------
 // Supporting structs
 // ---------------------------------------------------------------------------