[QoS][Cosmos SDK] Implement QoS for Cosmos SDK application layer

[commoddity]

Objective

Implement a QoS package in the qos/cosmos folder that implements QoS checks and endpoint selection for the Cosmos SDK application layer.

Origin Document

The current QoS module for CometBFT covers only the consensus layer. The objective of this issue is to create a QoS layer that covers the Cosmos SDK application layer.

For example, endpoints like:

• /cosmos/bank/v1beta1/balances
• /cosmos/staking/v1beta1/validators

Cosmos SDK API reference:
https://docs.cosmos.network/api

Goals

• Cosmos SDK endpoints (for example pocket) are correctly checked using relevant quality checks and filtered out from the qualified endpoints pool if they fail them
• Only good quality Cosmos SDK endpoints are selected from the available pool
• Any relevant documentation is updating

Deliverables

• Create a qos/cosmos package that utilizes the package structure defined in qos/evm (selected because it is the most developed of the existing QoS packages) to perform equivalent checks against Cosmos SDK endpoints
• Any relevant documentation that explains the Cosmos SDK selection process is updated
• pocket and other Cosmos SDK blockchains are updated in the config/service_qos_config.go file

Non-goals / Non-deliverables

• Archival checks for Cosmos SDK endpoints are not included in this issue

General deliverables

• Comments: Add/update TODOs and comments alongside the source code so it is easier to follow.
• Testing: Add new tests (unit and/or E2E) to the test suite.
• Makefile: Add new targets to the Makefile to make the new functionality easier to use.
• Documentation: Update architectural or development READMEs; use mermaid diagrams where appropriate.

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Creator: @commoddity
Co-Owners: @adshmh @Olshansk