feat(data): expand challenge seed pool with 75 verified wins

Adds a gen_seeds binary to solitaire_assetgen that brute-searches seeds
for hands solvable in ≤250 moves, then writes the list.  The 75 new
seeds (0xCAFEBABE prefix) are appended to CHALLENGE_SEEDS in
solitaire_data::challenge.

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

Cargo.lock

@@ -6967,6 +6967,8 @@ version = "0.1.0"
 dependencies = [
  "ab_glyph",
  "png 0.17.16",
+ "solitaire_core",
+ "solitaire_data",
 ]
 
 [[package]]

solitaire_assetgen/Cargo.toml

@@ -12,6 +12,8 @@ publish = false
 [dependencies]
 png     = "0.17"
 ab_glyph = "0.2"
+solitaire_core = { path = "../solitaire_core" }
+solitaire_data = { path = "../solitaire_data" }
 
 [[bin]]
 name = "gen_sfx"
@@ -20,3 +22,7 @@ path = "src/bin/gen_sfx.rs"
 [[bin]]
 name = "gen_art"
 path = "src/bin/gen_art.rs"
+
+[[bin]]
+name = "gen_seeds"
+path = "src/bin/gen_seeds.rs"

solitaire_assetgen/src/bin/gen_seeds.rs

@@ -0,0 +1,157 @@
+//! Generate provably-winnable Klondike seeds for `CHALLENGE_SEEDS`.
+//!
+//! Walks seeds incrementally from `--start`, calls the solver on each, and
+//! collects only those that return `SolverResult::Winnable` (Inconclusive is
+//! rejected — the curated list wants proof). Prints Rust source suitable for
+//! pasting into `solitaire_data/src/challenge.rs`.
+//!
+//! # Usage
+//!
+//! ```bash
+//! cargo run -p solitaire_assetgen --bin gen_seeds --release -- \
+//!     --start 0xCAFE_BABE_0000_0000 --count 75
+//! ```
+//!
+//! Flags:
+//!   --start  Starting seed (decimal or 0x-prefixed hex, default 0xCAFEBABE00000000)
+//!   --count  Number of Winnable seeds to emit (default 75)
+//!   --help   Print this message
+
+use solitaire_core::game_state::DrawMode;
+use solitaire_core::solver::{try_solve, SolverConfig, SolverResult};
+
+fn main() {
+    let mut args = std::env::args().skip(1).peekable();
+    let mut start: u64 = 0xCAFE_BABE_0000_0000;
+    let mut count: usize = 75;
+
+    while let Some(arg) = args.next() {
+        match arg.as_str() {
+            "--start" => {
+                let val = args.next().unwrap_or_else(|| {
+                    eprintln!("error: --start requires a value");
+                    std::process::exit(1);
+                });
+                start = parse_u64(&val);
+            }
+            "--count" => {
+                let val = args.next().unwrap_or_else(|| {
+                    eprintln!("error: --count requires a value");
+                    std::process::exit(1);
+                });
+                count = val.parse().unwrap_or_else(|_| {
+                    eprintln!("error: --count must be a positive integer");
+                    std::process::exit(1);
+                });
+            }
+            "--help" | "-h" => {
+                eprintln!("{}", include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/src/bin/gen_seeds.rs")).lines().take(20).collect::<Vec<_>>().join("\n"));
+                return;
+            }
+            other => {
+                eprintln!("error: unknown argument: {other}");
+                std::process::exit(1);
+            }
+        }
+    }
+
+    if count == 0 {
+        eprintln!("error: --count must be > 0");
+        std::process::exit(1);
+    }
+
+    let cfg = SolverConfig::default();
+    let draw_mode = DrawMode::DrawOne;
+    let mut found: Vec<u64> = Vec::with_capacity(count);
+    let mut tried: u64 = 0;
+    let mut seed = start;
+
+    eprintln!(
+        "gen_seeds: finding {count} Winnable seeds from 0x{start:016X} (DrawOne) …"
+    );
+
+    while found.len() < count {
+        tried += 1;
+        if matches!(
+            try_solve(seed, draw_mode.clone(), &cfg),
+            SolverResult::Winnable
+        ) {
+            found.push(seed);
+            eprintln!(
+                "  [{:>3}/{}]  0x{:016X}  ({} tried so far)",
+                found.len(),
+                count,
+                seed,
+                tried
+            );
+        }
+        seed = seed.wrapping_add(1);
+    }
+
+    eprintln!("\nDone. Paste the block below into CHALLENGE_SEEDS in solitaire_data/src/challenge.rs:\n");
+
+    println!(
+        "    // Generated by solitaire_assetgen::gen_seeds \
+         (start=0x{start:016X}, count={count}, date={date})",
+        date = current_date()
+    );
+    for chunk in found.chunks(5) {
+        for s in chunk {
+            println!(
+                "    0x{:04X}_{:04X}_{:04X}_{:04X},",
+                (s >> 48) & 0xFFFF,
+                (s >> 32) & 0xFFFF,
+                (s >> 16) & 0xFFFF,
+                s & 0xFFFF,
+            );
+        }
+        println!();
+    }
+}
+
+fn parse_u64(s: &str) -> u64 {
+    let cleaned = s.replace('_', "");
+    if let Some(hex) = cleaned.strip_prefix("0x").or_else(|| cleaned.strip_prefix("0X")) {
+        u64::from_str_radix(hex, 16).unwrap_or_else(|_| {
+            eprintln!("error: could not parse '{s}' as a hex u64");
+            std::process::exit(1);
+        })
+    } else {
+        cleaned.parse().unwrap_or_else(|_| {
+            eprintln!("error: could not parse '{s}' as a decimal u64");
+            std::process::exit(1);
+        })
+    }
+}
+
+fn current_date() -> String {
+    use std::time::{SystemTime, UNIX_EPOCH};
+    let secs = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0);
+    let days = secs / 86400;
+    // Gregorian calendar computation (Tomohiko Sakamoto's algorithm variant)
+    let mut y = 1970u64;
+    let mut d = days;
+    loop {
+        let leap = (y.is_multiple_of(4) && !y.is_multiple_of(100)) || y.is_multiple_of(400);
+        let days_in_year = if leap { 366 } else { 365 };
+        if d < days_in_year {
+            break;
+        }
+        d -= days_in_year;
+        y += 1;
+    }
+    let leap = (y.is_multiple_of(4) && !y.is_multiple_of(100)) || y.is_multiple_of(400);
+    let month_days: [u64; 12] = [31, if leap { 29 } else { 28 }, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
+    let mut m = 0usize;
+    for &md in &month_days {
+        if d < md {
+            break;
+        }
+        d -= md;
+        m += 1;
+    }
+    format!("{y}-{:02}-{:02}", m + 1, d + 1)
+}

solitaire_data/src/challenge.rs

@@ -40,6 +40,82 @@ pub const CHALLENGE_SEEDS: &[u64] = &[
     0xDDDD_EEEE_FFFF_0000,
     0x0101_0101_0101_0101,
     0xA1B2_C3D4_E5F6_0718,
+    // Generated by solitaire_assetgen::gen_seeds (start=0xCAFEBABE00000000, count=75, date=2026-05-09)
+    0xCAFE_BABE_0000_0000,
+    0xCAFE_BABE_0000_0002,
+    0xCAFE_BABE_0000_0004,
+    0xCAFE_BABE_0000_0008,
+    0xCAFE_BABE_0000_000B,
+    0xCAFE_BABE_0000_000D,
+    0xCAFE_BABE_0000_000E,
+    0xCAFE_BABE_0000_0010,
+    0xCAFE_BABE_0000_0011,
+    0xCAFE_BABE_0000_0014,
+    0xCAFE_BABE_0000_0016,
+    0xCAFE_BABE_0000_0019,
+    0xCAFE_BABE_0000_001A,
+    0xCAFE_BABE_0000_001F,
+    0xCAFE_BABE_0000_0020,
+    0xCAFE_BABE_0000_0021,
+    0xCAFE_BABE_0000_0024,
+    0xCAFE_BABE_0000_0025,
+    0xCAFE_BABE_0000_0027,
+    0xCAFE_BABE_0000_002B,
+    0xCAFE_BABE_0000_002D,
+    0xCAFE_BABE_0000_0030,
+    0xCAFE_BABE_0000_0034,
+    0xCAFE_BABE_0000_0036,
+    0xCAFE_BABE_0000_003A,
+    0xCAFE_BABE_0000_003B,
+    0xCAFE_BABE_0000_003D,
+    0xCAFE_BABE_0000_0042,
+    0xCAFE_BABE_0000_0043,
+    0xCAFE_BABE_0000_0044,
+    0xCAFE_BABE_0000_004C,
+    0xCAFE_BABE_0000_004D,
+    0xCAFE_BABE_0000_004F,
+    0xCAFE_BABE_0000_0050,
+    0xCAFE_BABE_0000_0051,
+    0xCAFE_BABE_0000_0054,
+    0xCAFE_BABE_0000_0055,
+    0xCAFE_BABE_0000_0056,
+    0xCAFE_BABE_0000_0059,
+    0xCAFE_BABE_0000_005B,
+    0xCAFE_BABE_0000_005C,
+    0xCAFE_BABE_0000_005E,
+    0xCAFE_BABE_0000_0060,
+    0xCAFE_BABE_0000_0062,
+    0xCAFE_BABE_0000_0064,
+    0xCAFE_BABE_0000_0067,
+    0xCAFE_BABE_0000_0069,
+    0xCAFE_BABE_0000_006A,
+    0xCAFE_BABE_0000_006B,
+    0xCAFE_BABE_0000_006C,
+    0xCAFE_BABE_0000_006D,
+    0xCAFE_BABE_0000_006E,
+    0xCAFE_BABE_0000_006F,
+    0xCAFE_BABE_0000_0072,
+    0xCAFE_BABE_0000_0073,
+    0xCAFE_BABE_0000_0074,
+    0xCAFE_BABE_0000_0079,
+    0xCAFE_BABE_0000_007A,
+    0xCAFE_BABE_0000_007D,
+    0xCAFE_BABE_0000_007E,
+    0xCAFE_BABE_0000_007F,
+    0xCAFE_BABE_0000_0082,
+    0xCAFE_BABE_0000_0083,
+    0xCAFE_BABE_0000_0084,
+    0xCAFE_BABE_0000_0085,
+    0xCAFE_BABE_0000_0089,
+    0xCAFE_BABE_0000_008A,
+    0xCAFE_BABE_0000_008D,
+    0xCAFE_BABE_0000_008E,
+    0xCAFE_BABE_0000_0090,
+    0xCAFE_BABE_0000_0094,
+    0xCAFE_BABE_0000_0095,
+    0xCAFE_BABE_0000_0098,
+    0xCAFE_BABE_0000_0099,
+    0xCAFE_BABE_0000_009F,
 ];
 
 /// Resolve a `challenge_index` to its corresponding seed, wrapping when