refactor(simulation): split atlas.rs subcommands into modules

Extract 2119-line monolithic atlas.rs into 8 focused modules under
src/bin/atlas/: main.rs (thin dispatch), common.rs (shared types and
DB helpers), show.rs, mutate.rs, stats.rs, systems.rs, author.rs,
and sync_wiki.rs. Commands enum stays in main.rs; each match arm
delegates to module::cmd_fn(&conn, args). No behavior change.

Closes #776.

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

server/src/bin/atlas/mutate.rs

@@ -0,0 +1,109 @@
+use std::process;
+
+use rusqlite::{params, Connection};
+use serde::Serialize;
+
+pub fn cmd_add_body(
+    conn: &Connection,
+    id: &str,
+    system: &str,
+    r#type: &str,
+    orbit: Option<i32>,
+    name: &Option<String>,
+    parent: &Option<String>,
+    mass_class: &Option<String>,
+    atmosphere: &Option<String>,
+    gravity: Option<f64>,
+    biome: &Option<String>,
+    inhabited: bool,
+    population: Option<i64>,
+) {
+    conn.execute(
+        "INSERT INTO bodies (body_id, system_id, parent_body_id, body_type, orbit_index,
+                             proper_name, mass_class, atmosphere, surface_gravity,
+                             biome_summary, inhabited, population)
+         VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12)",
+        params![
+            id,
+            system,
+            parent,
+            r#type,
+            orbit,
+            name,
+            mass_class,
+            atmosphere,
+            gravity,
+            biome,
+            inhabited as i32,
+            population.unwrap_or(0),
+        ],
+    )
+    .unwrap_or_else(|e| {
+        eprintln!("error: {}", e);
+        process::exit(1);
+    });
+
+    println!(r#"{{"ok": true, "body_id": "{}"}}"#, id);
+}
+
+pub fn cmd_add_station(
+    conn: &Connection,
+    id: &str,
+    system: &str,
+    orbits: &Option<String>,
+    r#type: &str,
+    name: &Option<String>,
+    population: Option<i64>,
+    docking: &Option<String>,
+    gate: bool,
+) {
+    conn.execute(
+        "INSERT INTO stations (station_id, system_id, orbits_body_id, station_type,
+                               proper_name, population, docking_class, has_gate_infrastructure)
+         VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
+        params![
+            id,
+            system,
+            orbits,
+            r#type,
+            name,
+            population.unwrap_or(0),
+            docking,
+            gate as i32,
+        ],
+    )
+    .unwrap_or_else(|e| {
+        eprintln!("error: {}", e);
+        process::exit(1);
+    });
+
+    println!(r#"{{"ok": true, "station_id": "{}"}}"#, id);
+}
+
+pub fn cmd_wipe_system(conn: &Connection, system_id: &str) {
+    let stations_deleted: usize = conn
+        .execute(
+            "DELETE FROM stations WHERE system_id = ?1",
+            params![system_id],
+        )
+        .unwrap();
+    let bodies_deleted: usize = conn
+        .execute(
+            "DELETE FROM bodies WHERE system_id = ?1",
+            params![system_id],
+        )
+        .unwrap();
+
+    #[derive(Serialize)]
+    struct WipeResult {
+        system_id: String,
+        bodies_deleted: usize,
+        stations_deleted: usize,
+    }
+    let result = WipeResult {
+        system_id: system_id.to_string(),
+        bodies_deleted,
+        stations_deleted,
+    };
+    println!("{}", serde_json::to_string_pretty(&result).unwrap());
+}