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, 16 insertions, 0 deletions

diff --git a/src/db.rs b/src/db.rs
index 7868e3e..2024032 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -62,6 +62,18 @@ impl Database {
                 updated_at   TEXT NOT NULL DEFAULT (datetime('now'))
             );
 
+            CREATE TABLE IF NOT EXISTS mods (
+                id              INTEGER PRIMARY KEY AUTOINCREMENT,
+                instance_id     INTEGER NOT NULL,
+                filename        TEXT NOT NULL,
+                display_name    TEXT,
+                side            TEXT NOT NULL DEFAULT 'UNKNOWN',
+                accepted        INTEGER NOT NULL DEFAULT 0,
+                rejection_reason TEXT,
+                created_at      TEXT NOT NULL DEFAULT (datetime('now')),
+                FOREIGN KEY (instance_id) REFERENCES instances(id) ON DELETE CASCADE
+            );
+
             CREATE TABLE IF NOT EXISTS backups (
                 id          INTEGER PRIMARY KEY AUTOINCREMENT,
                 instance_id INTEGER NOT NULL,
@@ -98,6 +110,10 @@ impl Database {
         let _ = conn.execute_batch(
             "ALTER TABLE instances ADD COLUMN container_state TEXT NOT NULL DEFAULT 'stopped'",
         );
+        // Migration: add whitelist_enabled column if missing
+        let _ = conn.execute_batch(
+            "ALTER TABLE instances ADD COLUMN whitelist_enabled INTEGER NOT NULL DEFAULT 1",
+        );
         Ok(())
     }