Add per-instance mod management with client-side detection

- New mod validation engine (src/mods.rs) with constant-pool class-file
  scanning: detects server-side content (block, tileentity, command,
  worldgen) vs client-only API (gui, renderer, forge/client)
- 7 client-only mods correctly detected (AppleSkin, CraftingTweaks,
  Durability101, EnchantmentDescriptions, InventoryHUD, MouseTweaks,
  TrashSlot); 51 server-capable; 1 unknown
- Routes + templating for mod upload (jar/zip), listing, delete, rescan
- Multipart upload with 500MB limit (bypasses axum's default 2MB)
- Per-instance mod summary card on edit page
- Whitelist toggle checkbox on edit page (persisted, drives ENABLE_WHITELIST)
- Dynamic Java image tag (java8/java17/java21) based on MC version
- Class scan is informational-only; rejection based on metadata side=CLIENT
- has_modpack flag cleanup on mod delete
- Remove hx-boost from <body> (was corrupting multipart uploads)

1 files changed, 46 insertions, 15 deletions

diff --git a/src/docker.rs b/src/docker.rs
index 6b8640a..d66767e 100644
--- a/src/docker.rs
+++ b/src/docker.rs
@@ -23,19 +23,51 @@ impl DockerManager {
         Ok(Self { client, config })
     }
 
+    /// Map a Minecraft version string (e.g. "1.12.2", "1.20.1") to the
+    /// appropriate itzg/minecraft-server Java image tag.
+    ///
+    /// - < 1.17       → java8   (Minecraft 1.12.2 and earlier)
+    /// - 1.17 .. 1.20.4 → java17
+    /// - >= 1.20.5    → java21
+    fn java_tag(version: &str) -> &'static str {
+        // Parse major.minor from version strings like "1.12.2", "1.20.1", "1.21"
+        let parts: Vec<&str> = version.split('.').collect();
+        if parts.len() < 2 {
+            return "java17"; // sensible default
+        }
+        let major: u32 = parts.first().and_then(|s| s.parse().ok()).unwrap_or(1);
+        let minor: u32 = parts.get(1).and_then(|s| s.parse().ok()).unwrap_or(12);
+
+        if major <= 1 && minor < 17 {
+            "java8"
+        } else if major <= 1 && minor < 21 {
+            // 1.17.x through 1.20.4 use Java 17
+            "java17"
+        } else {
+            // 1.20.5+ and 1.21+ use Java 21
+            "java21"
+        }
+    }
+
+    /// Build the full image reference, e.g. "itzg/minecraft-server:java8"
+    fn image_ref(version: &str) -> String {
+        format!("itzg/minecraft-server:{}", Self::java_tag(version))
+    }
+
     pub async fn start_container(&self, instance: &Instance) -> Result<(), String> {
-        tracing::info!("Pulling itzg/minecraft-server:latest image...");
-        self.pull_image().await?;
+        let tag = Self::java_tag(&instance.version);
+        tracing::info!("Pulling itzg/minecraft-server:{tag} image...");
+        self.pull_image(tag).await?;
         tracing::info!("Creating container for instance '{}'", instance.name);
         self.recreate_container(instance).await?;
         tracing::info!("Starting container...");
         self.start_existing().await
     }
 
-    async fn pull_image(&self) -> Result<(), String> {
+    async fn pull_image(&self, tag: &str) -> Result<(), String> {
         let options = CreateImageOptions {
             from_image: "itzg/minecraft-server",
-            tag: "latest",
+            tag,
             ..Default::default()
         };
 
@@ -74,6 +106,8 @@ impl DockerManager {
             .to_string();
         let instance_data = format!("{server_dir}/instances/{}/data", instance.name);
 
+        let image_ref = Self::image_ref(&instance.version);
+
         let mut env_strings: Vec<String> = vec![
             "EULA=TRUE".into(),
             format!("VERSION={}", instance.version),
@@ -83,7 +117,7 @@ impl DockerManager {
             format!("DIFFICULTY={}", instance.difficulty),
             "FORCE_GAMEMODE=true".into(),
             "SPAWN_PROTECTION=0".into(),
-            "ENABLE_WHITELIST=true".into(),
+            format!("ENABLE_WHITELIST={}", instance.whitelist_enabled),
             "PAUSE_WHEN_EMPTY_SECONDS=30".into(),
             "ONLINE_MODE=false".into(),
             "TZ=Europe/Warsaw".into(),
@@ -102,17 +136,14 @@ impl DockerManager {
             env_strings.push("PVP=false".into());
         }
 
-        if let Some(ref seed) = instance.world_seed {
-            if !seed.is_empty() {
+        if let Some(ref seed) = instance.world_seed
+            && !seed.is_empty() {
                 env_strings.push(format!("LEVEL_SEED={seed}"));
             }
-        }
-
-        let env_refs: Vec<&str> = env_strings.iter().map(|s| s.as_str()).collect();
 
-        let mut exposed_ports: HashMap<&str, HashMap<(), ()>> = HashMap::new();
-        exposed_ports.insert("25565/tcp", HashMap::new());
-        exposed_ports.insert("25575/tcp", HashMap::new());
+        let mut exposed_ports: HashMap<String, HashMap<(), ()>> = HashMap::new();
+        exposed_ports.insert("25565/tcp".into(), HashMap::new());
+        exposed_ports.insert("25575/tcp".into(), HashMap::new());
 
         let mut port_bindings = HashMap::new();
         port_bindings.insert(
@@ -137,9 +168,9 @@ impl DockerManager {
         };
 
         let container_config = ContainerConfig {
-            image: Some("itzg/minecraft-server:latest"),
+            image: Some(image_ref.clone()),
             tty: Some(true),
-            env: Some(env_refs),
+            env: Some(env_strings.clone()),
             exposed_ports: Some(exposed_ports),
             host_config: Some(host_config),
             ..Default::default()