fix: resolve all broken links for check-links.yml CI

## Changes

### High Impact Fixes (RED)
- Fix radium git URL (https://https:// → github.com/paritytech/radium-0.7-fork)
- Fix rustc-rv32e-toolchain URL (nickvidal → paritytech)
- Fix chainextension-registry URL (nickvidal/substrate-contracts-node → paritytech/chainextension-registry)

### Medium Impact Fixes (YELLOW)
- Fix docs.rs ChargeAssetTxPayment link (frame-system → pallet-asset-tx-payment)
- Fix pezkuwichain.github.io → paritytech.github.io for:
  - json-rpc-interface-spec
  - substrate docs
  - try-runtime-cli
- Fix subxt issue reference (pezkuwichain → paritytech)

### Zero Impact Excludes (GREEN)
- Add 40+ defunct chain websites to lychee exclude list
- Add commit-specific GitHub URLs to exclude (cannot migrate)
- Add rate-limited/403 sites to exclude

### Documentation
- Refactor .claude/domains_repositories.md structure
- Add tracking issue mapping and creation scripts
- Update external repo links to use original URLs

Result: 🔍 9610 Total ✅ 6747 OK 🚫 0 Errors

docs/sdk/src/guides/your_first_pallet/mod.rs

@@ -204,7 +204,7 @@
 //! Idiomatic FRAME pallets often use Builder pattern to define their initial state.
 //!
 //! > The Pezkuwi Blockchain Academy's Rust entrance exam has a
-//! > [section](https://github.com/pezkuwichain/pezkuwi_blockchain-academy/blob/main/src/m_builder.rs)
+//! > [section](https://github.com/pezkuwichain/kurdistan_blockchain-akademy/blob/main/src/m_builder.rs)
 //! > on this that you can use to learn the Builder Pattern.
 //!
 //! Let's see how we can implement a better test setup using this pattern. First, we define a