feat: Rebrand Polkadot/Substrate references to PezkuwiChain

This commit systematically rebrands various references from Parity Technologies'
Polkadot/Substrate ecosystem to PezkuwiChain within the kurdistan-sdk.

Key changes include:
- Updated external repository URLs (zombienet-sdk, parity-db, parity-scale-codec, wasm-instrument) to point to pezkuwichain forks.
- Modified internal documentation and code comments to reflect PezkuwiChain naming and structure.
- Replaced direct references to  with  or specific paths within the  for XCM, Pezkuwi, and other modules.
- Cleaned up deprecated  issue and PR references in various  and  files, particularly in  and  modules.
- Adjusted image and logo URLs in documentation to point to PezkuwiChain assets.
- Removed or rephrased comments related to external Polkadot/Substrate PRs and issues.

This is a significant step towards fully customizing the SDK for the PezkuwiChain ecosystem.

bizinikiwi/client/db/src/children.rs

@@ -0,0 +1,123 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Functionality for reading and storing children hashes from db.
+
+use crate::DbHash;
+use codec::{Decode, Encode};
+use pezsp_blockchain;
+use pezsp_database::{Database, Transaction};
+use std::hash::Hash;
+
+/// Returns the hashes of the children blocks of the block with `parent_hash`.
+pub fn read_children<
+	K: Eq + Hash + Clone + Encode + Decode,
+	V: Eq + Hash + Clone + Encode + Decode,
+>(
+	db: &dyn Database<DbHash>,
+	column: u32,
+	prefix: &[u8],
+	parent_hash: K,
+) -> pezsp_blockchain::Result<Vec<V>> {
+	let mut buf = prefix.to_vec();
+	parent_hash.using_encoded(|s| buf.extend(s));
+
+	let raw_val_opt = db.get(column, &buf[..]);
+
+	let raw_val = match raw_val_opt {
+		Some(val) => val,
+		None => return Ok(Vec::new()),
+	};
+
+	let children: Vec<V> = match Decode::decode(&mut &raw_val[..]) {
+		Ok(children) => children,
+		Err(_) => return Err(pezsp_blockchain::Error::Backend("Error decoding children".into())),
+	};
+
+	Ok(children)
+}
+
+/// Insert the key-value pair (`parent_hash`, `children_hashes`) in the transaction.
+/// Any existing value is overwritten upon write.
+pub fn write_children<
+	K: Eq + Hash + Clone + Encode + Decode,
+	V: Eq + Hash + Clone + Encode + Decode,
+>(
+	tx: &mut Transaction<DbHash>,
+	column: u32,
+	prefix: &[u8],
+	parent_hash: K,
+	children_hashes: V,
+) {
+	let mut key = prefix.to_vec();
+	parent_hash.using_encoded(|s| key.extend(s));
+	tx.set_from_vec(column, &key[..], children_hashes.encode());
+}
+
+/// Prepare transaction to remove the children of `parent_hash`.
+pub fn remove_children<K: Eq + Hash + Clone + Encode + Decode>(
+	tx: &mut Transaction<DbHash>,
+	column: u32,
+	prefix: &[u8],
+	parent_hash: K,
+) {
+	let mut key = prefix.to_vec();
+	parent_hash.using_encoded(|s| key.extend(s));
+	tx.remove(column, &key);
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use std::sync::Arc;
+
+	#[test]
+	fn children_write_read_remove() {
+		const PREFIX: &[u8] = b"children";
+		let db = Arc::new(pezsp_database::MemDb::default());
+
+		let mut tx = Transaction::new();
+
+		let mut children1 = Vec::new();
+		children1.push(1_3);
+		children1.push(1_5);
+		write_children(&mut tx, 0, PREFIX, 1_1, children1);
+
+		let mut children2 = Vec::new();
+		children2.push(1_4);
+		children2.push(1_6);
+		write_children(&mut tx, 0, PREFIX, 1_2, children2);
+
+		db.commit(tx.clone()).unwrap();
+
+		let r1: Vec<u32> = read_children(&*db, 0, PREFIX, 1_1).expect("(1) Getting r1 failed");
+		let r2: Vec<u32> = read_children(&*db, 0, PREFIX, 1_2).expect("(1) Getting r2 failed");
+
+		assert_eq!(r1, vec![1_3, 1_5]);
+		assert_eq!(r2, vec![1_4, 1_6]);
+
+		remove_children(&mut tx, 0, PREFIX, 1_2);
+		db.commit(tx).unwrap();
+
+		let r1: Vec<u32> = read_children(&*db, 0, PREFIX, 1_1).expect("(2) Getting r1 failed");
+		let r2: Vec<u32> = read_children(&*db, 0, PREFIX, 1_2).expect("(2) Getting r2 failed");
+
+		assert_eq!(r1, vec![1_3, 1_5]);
+		assert_eq!(r2.len(), 0);
+	}
+}