fix crash during apply_proof with DAG level 0 blocks referencing origin

[x100111010]

Fixes a crash that occurs at let calculated_gd = self.ghostdag_manager.ghostdag(&parents) when processing the first block in proof[0] (DAG level 0).

2025-06-18 21:39:18.547+02:00 [ERROR] thread 'tokio-runtime-worker' panicked at consensus\src\processes\ghostdag\protocol.rs:103:110: called Result::unwrap()on anErr value: KeyNotFound(GhostdagCompact/0/fefefefefefefefefefefefefefefefefefefefefefefefefefefefefefefefe)

The crash happens during apply_proof when processing DAG level 0 blocks. The root cause is in the parent filtering logic using level ancestors:

.filter(|parent| level_ancestors.contains(parent))

When this filtering removes all parents (because they're not in the level ancestors set) it code falls back to using [ORIGIN] as parents via .push_if_empty(ORIGIN).

For the first block in level 0 this results in parents containing only [ORIGIN]. When ghostdag() is called, it invokes find_selected_parent() which tries to read ORIGIN's blue work from the ghostdag store via get_blue_work(parent).unwrap(). But ORIGIN's ghostdag data was never inserted into the store, causing KeyNotFound(GhostdagCompact/0/fefe...) panic.

https://gist.github.com/x100111010/2189956eacc3559bae9da889422a1b87

ORIGIN is a special virtual genesis block:

pub const ORIGIN: Hash = Hash::from_bytes([0xfe; HASH_SIZE]);

Spectre has significantly more dag level 0 blocks (stems from large hashrate spikes that the Difficulty Adjustment Algorithm (DAA) cannot respond to quickly enough) blocks at DAG level 0 (98,969 blocks vs Kaspa's typically empty level 0), making proof[0] non-empty.

Found sufficient root for level 0 after 0 tries: 93544d1ec38f6c8ebc84ed24f10fe39392b2fc55a053e3951191dd568ac97d04

2025-06-19 16:48:54.683+02:00 [INFO ] Block 93544d1ec38f6c8ebc84ed24f10fe39392b2fc55a053e3951191dd568ac97d04 got fefe (ORIGIN)

2025-06-19 16:48:54.683+02:00 [INFO ] Is first block in level 0: true

2025-06-19 00:06:22.358+02:00 [INFO ] Level: 1 | Hash: 93544d1ec38f6c8ebc84ed24f10fe39392b2fc55a053e3951191dd568ac97d04 | Parents: [af623d9853b88ff737ad163d2f7d2199d38c30091297e196bff110dc65317af5]
2025-06-19 00:06:22.360+02:00 [INFO ] Parent: af623d9853b88ff737ad163d2f7d2199d38c30091297e196bff110dc65317af5 => dag level 1

2025-06-18 21:39:18.547+02:00 [ERROR] thread 'tokio-runtime-worker' panicked at consensus\src\processes\ghostdag\protocol.rs:103:110: called `Result::unwrap()` on an `Err` value: KeyNotFound(GhostdagCompact/0/fefefefefefefefefefefefefefefefefefefefefefefefefefefefefefefefe)