refactor(ci): decouple from upstream Parity infrastructure

Replace Parity-specific infrastructure dependencies with Pezkuwi's own:
- S3 release uploads → GitHub Releases (gh CLI)
- parity-zombienet runner labels → pezkuwi-runner
- Grafana/Loki log URLs → disabled (use GH artifacts)
- Matrix notifications → disabled (pending Pezkuwi Matrix)
- paritytech issue links → pezkuwi tracking issues
- paritytech Docker image refs → pezkuwi-sdk-frame in cmd.py
- Add mirror-ci-image.yml workflow for GHCR image mirroring
- Document upstream shared tools (resolc, try-runtime, evm-test-suite)

.github/scripts/check-each-crate.py

@@ -3,7 +3,7 @@
 # A script that checks each workspace crate individually.
 # It's relevant to check workspace crates individually because otherwise their compilation problems
 # due to feature misconfigurations won't be caught, as exemplified by
-# https://github.com/paritytech/substrate/issues/12705
+# https://github.com/pezkuwichain/pezkuwi-sdk/issues/163 (upstream tracking)
 #
 # `check-each-crate.py target_group groups_total`
 #