re: runtime DATA SHEET reads the live weapon record (Route B, first capture)

Drove the retail game headless (Canary + lavapipe, vgamepad) to the Ready Room
Arsenal and read the Gallery-Mode DATA SHEET for every weapon the 5%-progress
save reveals.

Two UI->field mappings are CONFIRMED against weapons whose values ARE on disc:
  Ammo Capacity  == LoadingCount      (9/9 exact matches)
  Max. Lock Ons  == TriggerShotCount  (FALCON 9AM 12 == wep_02; BUZZARD 22 == wep_04)

That makes the panel an oracle for fields the disc leaves defaulted, and it is
shown for undeveloped weapons too, so no points need spending. Recovered
TriggerShotCount for wep_05 and wep_60 (both 4, on-disc absent), and bracketed
the defaulted Power / MaximumRange via the Range/Damage letter classes.

Ruled out first: the defaults are not in hidden/DefTables.pak (no WEAPON-schema
objects there) nor in the localized GP_MAIN_GAME_* duplicates.

Also adds the two analysis examples that produce the shopping list of defaulted
fields, the screenshot harness used to drive the menus, and the evidence PNGs.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

crates/sylpheed-formats/examples/defaulted_fields.rs

@@ -0,0 +1,135 @@
+//! Scratch analysis: which IDXD fields are DECLARED but left at their default on
+//! disc, per schema. Those defaults live in title code, so they can only be read
+//! from the running game — this prints the shopping list for that dynamic capture.
+//!
+//! Run: cargo run -p sylpheed-formats --example defaulted_fields -- <disc-root>
+
+use std::collections::{BTreeMap, BTreeSet};
+use sylpheed_formats::idxd::IdxdObject;
+use sylpheed_formats::pak::PakArchive;
+
+fn is_number(s: &str) -> bool {
+    let s = s.strip_suffix(['f', 'F']).unwrap_or(s);
+    let t = s.strip_prefix(['-', '+']).unwrap_or(s);
+    !t.is_empty() && t.chars().all(|c| c.is_ascii_digit() || c == '.')
+}
+
+/// Same shape-test the parser uses: an identifier-looking token that is not a
+/// value literal is a field-name key.
+fn is_key(s: &str) -> bool {
+    !s.is_empty()
+        && s.chars()
+            .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
+        && s.chars().next().is_some_and(|c| c.is_ascii_alphabetic() || c == '_')
+        && !is_number(s)
+}
+
+fn is_value(s: &str) -> bool {
+    is_number(s) || !is_key(s)
+}
+
+fn main() {
+    let root = std::env::args()
+        .nth(1)
+        .unwrap_or_else(|| "/home/fabi/RE - Project Sylpheed/sylph_extract".into());
+    let paks: Vec<String> = std::env::args().skip(2).collect();
+    let paks = if paks.is_empty() {
+        vec![
+            "dat/GP_MAIN_GAME_E.pak".to_string(),
+            "dat/GP_HANGAR_ARSENAL.pak".to_string(),
+        ]
+    } else {
+        paks
+    };
+
+    for pak_rel in &paks {
+        let path = std::path::Path::new(&root).join(pak_rel);
+        let Ok(arc) = PakArchive::open(&path) else {
+            eprintln!("-- skip {pak_rel} (open failed)");
+            continue;
+        };
+        println!("\n================ {pak_rel} ================");
+
+        // schema -> key -> (n_set, n_defaulted, distinct values, example owners)
+        type Stat = (usize, usize, BTreeSet<String>, Vec<String>);
+        let mut per_schema: BTreeMap<u32, (usize, BTreeMap<String, Stat>)> = BTreeMap::new();
+
+        for e in arc.entries() {
+            let Ok(bytes) = arc.read(e) else { continue };
+            let Ok(obj) = IdxdObject::parse(&bytes) else {
+                continue;
+            };
+            let ident = obj.identity();
+            let toks = obj.tokens().to_vec();
+            let entry = per_schema.entry(obj.schema_hash).or_default();
+            entry.0 += 1;
+            // Track which keys this object declares, and whether each is valued.
+            let mut seen_here: BTreeMap<String, Option<String>> = BTreeMap::new();
+            for (i, t) in toks.iter().enumerate() {
+                if !is_key(t) {
+                    continue;
+                }
+                let prev = if i == 0 { None } else { Some(&toks[i - 1]) };
+                let valued = prev.map(|p| is_value(p)).unwrap_or(false);
+                let v = if valued { Some(toks[i - 1].clone()) } else { None };
+                seen_here.entry(t.clone()).or_insert(v);
+            }
+            for (k, v) in seen_here {
+                let s = entry.1.entry(k).or_default();
+                match v {
+                    Some(val) => {
+                        s.0 += 1;
+                        if s.2.len() < 12 {
+                            s.2.insert(val);
+                        }
+                    }
+                    None => {
+                        s.1 += 1;
+                        if s.3.len() < 6 {
+                            s.3.push(ident.clone());
+                        }
+                    }
+                }
+            }
+        }
+
+        for (schema, (n_obj, keys)) in per_schema {
+            if n_obj < 2 {
+                continue;
+            }
+            let name = match schema {
+                0x0426_e81d => "PLAYER",
+                0x6ab4_825a => "WEAPON",
+                0x43fa_a517 => "UNIT",
+                0x3c5b_0549 => "VESSEL",
+                0xbd86_d41c => "CHARACTER",
+                0x3c9a_e32e => "STAGE",
+                0xb412_e6d8 => "MESSAGE",
+                _ => "?",
+            };
+            let defaulted: Vec<_> = keys
+                .iter()
+                .filter(|(_, s)| s.1 > 0)
+                .collect();
+            if defaulted.is_empty() {
+                continue;
+            }
+            println!("\n--- schema 0x{schema:08x} {name}  ({n_obj} objects) ---");
+            println!(
+                "{:<30} {:>5} {:>5}   {}",
+                "KEY", "set", "dflt", "values seen (≤12) | owners defaulting"
+            );
+            for (k, (n_set, n_def, vals, owners)) in defaulted {
+                let vv: Vec<&str> = vals.iter().map(|s| s.as_str()).collect();
+                println!(
+                    "{:<30} {:>5} {:>5}   {} | {}",
+                    k,
+                    n_set,
+                    n_def,
+                    vv.join(","),
+                    owners.join(",")
+                );
+            }
+        }
+    }
+}