Add SNOS RPC method duration metrics on v0.22.2

[heemankv]

Summary

• base this change directly on upstream EQLabs Pathfinder v0.22.2 tag commit 95062ff7f1913958f5a8df71790a56263731e908
• add a SNOS-specific RPC duration histogram for the three methods SNOS calls heavily
• record durations as seconds with only the method label to keep cardinality bounded
• add a manual GHCR image build path using Blacksmith and linux/amd64

Metric

pathfinder_snos_rpc_method_duration_seconds{method}

Tracked methods:

• starknet_getStorageProof
• starknet_getClass
• starknet_getClassHashAt

Validation

• cargo check -p pathfinder-rpc

Image

Manual Docker workflow succeeded: https://github.com/karnotxyz/pathfinder/actions/runs/28112883437

Published image:

• ghcr.io/karnotxyz/pathfinder:manual-f996364
• digest: sha256:1322c3acf5043fdcd909c4e616ba57c3194a6d6f57c368bb54d8c49f3f17c1cc
• platform: linux/amd64
• build version: v0.22.2-1-gf9963643d

Earlier successful image manual-d22798f is functionally valid, but its embedded build version was only the commit SHA because the CI run did not yet fetch upstream EQLabs tags before git describe.