Complete rebrand: Polkadot→Pezkuwi, Substrate→Bizinikiwi

- Replace PolkadotConfig with PezkuwiConfig
- Replace SubstrateConfig with BizinikiwConfig
- Rename config module files (polkadot.rs→pezkuwi.rs, substrate.rs→bizinikiwi.rs)
- Update all documentation and examples
- All 165 files updated, cargo check passes

lightclient/Cargo.toml

@@ -12,7 +12,7 @@ repository.workspace = true
 documentation.workspace = true
 homepage.workspace = true
 description = "Light Client for chain interaction"
-keywords = ["blockchain", "parity", "substrate"]
+keywords = ["blockchain", "parity", "bizinikiwi"]
 
 [lints]
 workspace = true