game_data: Arsenal loader — player weapon options per hardpoint

Decode the player weapon arsenal from the UNITS tables
(GP_HANGAR_ARSENAL.pak): the selectable weapons per Delta Saber
hardpoint. Each `STANDARD_<hp>` header (Nose / Arm1-3) lists its options
up to the next header — extracted by shape, unioned + deduped across
configs.

The arsenal reads with the game's own names: NOSE guns (Stiletto,
Rapier, Broad Sword, Machine Cannon), ARM missiles/bombs (Falcon, Eagle,
White Shark, Piranha, Tomahawk Rail Gun, Maelstrom Bomb). Example
`arsenal` prints them. +1 test.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/sylpheed-formats/examples/arsenal.rs

@@ -0,0 +1,9 @@
+use sylpheed_formats::{game_data as gd, PakArchive};
+fn main(){
+    let disc=std::env::var("SYLPHEED_DISC").unwrap();
+    let pak=PakArchive::open(format!("{disc}/dat/GP_HANGAR_ARSENAL.pak")).unwrap();
+    let a=gd::load_arsenal(&pak);
+    for (hp,list) in [("NOSE",&a.nose),("ARM1",&a.arm1),("ARM2",&a.arm2),("ARM3",&a.arm3)]{
+        println!("{hp} ({}): {:?}", list.len(), list.iter().take(8).collect::<Vec<_>>());
+    }
+}

crates/sylpheed-formats/src/game_data.rs

@@ -689,6 +689,69 @@ pub fn load_pilot_rosters(pak: &PakArchive) -> Vec<PilotRoster> {
     out
 }
 
+// ── Arsenal (player weapon options per hardpoint) ───────────────────────────────
+
+/// The player's selectable weapons, by hardpoint (from the `UNITS` player-unit
+/// tables in `GP_HANGAR_ARSENAL.pak`). These are the arsenal display ids — the
+/// Delta Saber's nose guns (`Stiletto_BG1`, `Broad_Sword_SG1`, …) and arm missiles
+/// (`Falcon_9AM`, `White_Shark_T53R`, …) the player equips in the hangar.
+#[derive(Debug, Clone, Default)]
+pub struct Arsenal {
+    /// Nose slot — the fixed forward gun options.
+    pub nose: Vec<String>,
+    /// The three arm hardpoints — missile / bomb / special options.
+    pub arm1: Vec<String>,
+    pub arm2: Vec<String>,
+    pub arm3: Vec<String>,
+}
+
+/// The weapon ids listed under a `STANDARD_<hp>` header (skipping its `Type` key),
+/// up to the next `STANDARD_`/`PlayerSET_` header.
+fn hardpoint_options(tokens: &[String], header: &str) -> Vec<String> {
+    let Some(start) = tokens.iter().position(|s| s == header) else { return Vec::new() };
+    tokens[start + 1..]
+        .iter()
+        .skip_while(|s| *s == "Type")
+        .take_while(|s| !s.starts_with("STANDARD_") && !s.starts_with("PlayerSET"))
+        .filter(|s| *s != "Type")
+        .cloned()
+        .collect()
+}
+
+/// Load the player arsenal from a pak (`GP_HANGAR_ARSENAL.pak`). Unions the weapon
+/// options across every player-unit config, deduped in first-seen order.
+pub fn load_arsenal(pak: &PakArchive) -> Arsenal {
+    let mut a = Arsenal::default();
+    let mut seen = [(); 4].map(|_| std::collections::BTreeSet::new());
+    let slots: [(&str, usize); 4] = [
+        ("STANDARD_NOSE", 0),
+        ("STANDARD_ARM1", 1),
+        ("STANDARD_ARM2", 2),
+        ("STANDARD_ARM3", 3),
+    ];
+    for e in pak.entries() {
+        let Ok(b) = pak.read(e) else { continue };
+        let Ok(o) = IdxdObject::parse(&b) else { continue };
+        if !o.tokens().first().is_some_and(|s| s.ends_with("UNITS")) {
+            continue;
+        }
+        for (header, idx) in slots {
+            let dst = match idx {
+                0 => &mut a.nose,
+                1 => &mut a.arm1,
+                2 => &mut a.arm2,
+                _ => &mut a.arm3,
+            };
+            for w in hardpoint_options(o.tokens(), header) {
+                if seen[idx].insert(w.clone()) {
+                    dst.push(w);
+                }
+            }
+        }
+    }
+    a
+}
+
 // ── Generic record access (any of the ~105 schemas) ─────────────────────────────
 
 /// A generically-decoded IDXD record: its table name, schema id, identity, and
@@ -888,6 +951,20 @@ mod tests {
         assert!(rosters.iter().any(|r| r.pilots.iter().any(|(cs, _)| cs.starts_with("Bird"))));
     }
 
+    #[test]
+    fn loads_arsenal() {
+        let Ok(disc) = std::env::var("SYLPHEED_DISC") else { return };
+        let Ok(pak) = PakArchive::open(format!("{disc}/dat/GP_HANGAR_ARSENAL.pak")) else { return };
+        let a = load_arsenal(&pak);
+        assert!(a.nose.len() >= 5 && a.arm1.len() >= 5, "nose {} arm1 {}", a.nose.len(), a.arm1.len());
+        assert!(a.nose.iter().any(|w| w.starts_with("Stiletto")));
+        assert!(a.arm1.iter().any(|w| w.starts_with("Falcon")));
+        // Headers never leak into the option lists.
+        assert!([&a.nose, &a.arm1, &a.arm2, &a.arm3]
+            .iter()
+            .all(|v| v.iter().all(|w| !w.starts_with("STANDARD_") && *w != "Type")));
+    }
+
     #[test]
     fn generic_records_read_any_schema() {
         let Some(pak) = pak() else { return };