fix tn-12 branch + ports, drop redundant clone, remove .khost-data ignore

[demisrael]

Proposed fixes for PR aspectron#3, posted as a PR against your branch so you can review/merge/close rather than having edits land directly. Builds cleanly on Ubuntu 24.04 (rustc 1.95.0) and macOS 15.6.1 (rustc 1.81.0); clippy clean.

Changes

1. src/kaspad.rs — port collision

The current entry has tn-12 sharing wrpc ports with tn-10:

Network::Mainnet   => (16110, 17110, 18110),
Network::Testnet10 => (16210, 17210, 18210),
Network::Testnet12 => (16311, 17210, 18210),  // <-- wrpc collides with tn-10

Fixed to follow the netsuffix-numbered pattern: (16312, 17312, 18312).

2. covpp → tn12 (official upstream branch)

The covpp branch on kaspanet/rusty-kaspa no longer exists (404). The official tn-12 work is now on the tn12 branch (b97d108…) and includes Update genesis for TN12 launch 3, Add Toccata lane/gas limits to consensus, etc. — none of which are on aspectron/rusty-kaspa#pnn-v1, so the dual-origin design is still required for tn-12 to work.

Updated:

• src/config.rs: covpp_origin → tn12_origin, branch "covpp" → "tn12".
• src/git.rs: Preset::Covpp → Preset::Tn12, label and branch updated.

3. .gitignore — drop .khost-data

folders.rs defines DATA_FOLDER_NAME = ".khost" (Linux) / 00-khost-dev (other). .khost-data doesn't match either — looks like a stray from local Docker testing.

4. src/config.rs — redundant clone

let selected_origin = match network { … };  // already produces owned Origin
kaspad::Config::new(selected_origin.clone(), network)  // clone unnecessary

Dropped the trailing .clone().

Out of scope (separate PR)

The config v2→v3 migration for existing users with "testnet11" entries — that's a multi-file change touching Config::load() and probably best handled separately.