[Feature Request] Server Resources sync — allow server owners to publish required client files, downloaded automatically before connect.

[staark-dev]

Summary

Server owners currently have no official way to distribute required client-side resources (custom ASI plugins, CLEO scripts, textures, models) to players. Players either miss required files and get a degraded experience, or server owners resort to forum posts and manual instructions.
This proposal adds a Server Resources system — similar to FastDL in Garry’s Mod or resource sync in FiveM — directly into the open.mp launcher.

Problem

•	Servers that require custom client mods have no reliable distribution channel
•	Players join with missing or outdated files, causing visual glitches or missing features
•	Server owners resort to Discord pins, forum posts, or third-party installers
•	No integrity checking — players may have modified local files that differ from the server’s expected versions

Proposed Solution

A two-part system: a resource manifest published by the server, and automatic sync in the launcher before connecting.

Part 1 — Resource Manifest (server side)

Each server optionally publishes a JSON manifest at a URL declared in its SA:MP rules (via AddServerRule in Pawn):

// On the server (gamemode)
AddServerRule("omp_resources", "https://cdn.myserver.com/resources.json");
```

The manifest format:
```
{
  "version": 1,
  "resources": [
    {
      "name": "myserver_hud.asi",
      "url": "https://cdn.myserver.com/files/myserver_hud.asi",
      "sha256": "a3f1c2...",
      "version": "1.2.0",
      "destination": "modloader",
      "required": true
    },
    {
      "name": "myserver_vehicles.txd",
      "url": "https://cdn.myserver.com/files/myserver_vehicles.txd",
      "sha256": "b7e9d1...",
      "version": "3.0.1",
      "destination": "models/txd",
      "required": false
    }
  ]
}
```

### Fields:
	•	destination — relative path inside GTA:SA folder (modloader, cleo, models/txd, models/dff)
	•	required — if true, launcher warns and blocks connecting if file is missing or hash doesn’t match
	•	sha256 — integrity check, compared against local file hash before downloading

##Part 2 — Launcher behavior (client side)

When a player clicks Connect on a server that has omp_resources in its rules:
	1.	Launcher fetches the manifest URL
	2.	Compares each resource against local files (path + SHA-256 hash)
	3.	Shows a dialog:
	•	✓ All files up to date → connect immediately
	•	⬇ N files need download → show list + “Download and Connect” button
	•	Required files missing → “Download required” (can’t skip), optional files can be skipped
	4.	Downloads missing/outdated files with a per-file progress bar
	5.	Files are placed in the correct GTA:SA subdirectory
	6.	Launcher proceeds to connect
Optional UX addition: a dedicated Server Resources sub-tab in the server detail panel showing the resource list and local sync status at a glance.

##Security considerations

Only files declared in the manifest are downloaded
	•	SHA-256 hash verification before the file is moved into place — corrupted or tampered downloads are rejected
	•	Files are placed only in declared destination paths within the GTA:SA folder — no arbitrary write paths
	•	The manifest URL must use HTTPS
	•	Server owners are responsible for their CDN content — this is consistent with how SA:MP already works (servers can inject Pawn scripts into clients)

##Why this belongs in the launcher

The launcher is the only component that:
	•	Knows the local GTA:SA path
	•	Has file system access before the game starts
	•	Already queries server rules via UDP before connecting
	•	Has the user’s attention at the exact right moment (pre-connect)
This cannot be done inside the game client itself without significant complexity.


##Implementation notes

Manifest URL read from server rules (already fetched during server query)
	•	File download: Rust reqwest crate (already in Cargo.toml as a dependency)
	•	Hash verification: Rust sha2 crate
	•	Frontend: modal dialog + progress bars in React, consistent with existing join modal
	•	No new backend infrastructure required for server owners — any static file hosting works (CDN, GitHub Releases, S3, even a simple nginx)

###Prior art

Garry’s Mod FastDL — server-declared file server, client downloads before map load
	•	FiveM / RedM — full resource streaming system built into the client
	•	Counter-Strike — sv_downloadurl for custom content
	•	MTA:SA — built-in resource download system
All major SA-adjacent multiplayer mods have solved this problem. SA:MP never did. This is an opportunity for open.mp to set a new standard.


## Willingness to contribute

I have a working UI prototype of both the client-side resource sync flow and the owner-side manifest configuration panel. I am willing to implement this and submit a PR. Looking for team feedback on:
	1.	Whether omp_resources server rule is the right mechanism, or if there’s a better hook
	2.	Preferred approach for the download dialog UX
	3.	Any security concerns I may have missed