feat: add WebSocket support for REST API interface

[nimrod-teich]

This adds WebSocket support for REST POST requests with plain JSON payloads, enabling chains like Stellar/XRP that use WebSocket with non-JSON-RPC messages.

Key changes:

• Add RestWebsocketManager for consumer-side plain JSON WebSocket handling
• Add RestWsConnector and RestWsConnection for provider-side WebSocket pool
• Add RestWsChainProxy for provider to communicate with node over WebSocket
• Modify RestChainParser to handle 'WEBSOCKET' connection type
• Update ChainRouter to select WebSocket proxy when node URL is ws/wss
• Allow ws/wss schemes in REST API endpoint validation
• Propagate 'websocket' extension via AdditionalExtensions in relay data

The implementation mirrors the existing JSON-RPC WebSocket pattern:

1. Consumer opens WebSocket, extracts 'command' or 'method' from JSON
2. Consumer communicates with provider via gRPC with 'websocket' extension
3. Provider routes to RestWsChainProxy which sends plain JSON to node

Description

Closes: #XXXX

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[github-actions]

Test Results

    4 files   -     1     56 suites   - 71   14m 34s ⏱️ - 4m 58s
1 617 tests  - 1 290  1 613 ✅  - 1 285  1 💤 ±0  3 ❌ +1 
1 697 runs   - 1 290  1 693 ✅  - 1 285  1 💤 ±0  3 ❌ +1 

For more details on these failures, see this check.

Results for commit 91882aa. ± Comparison against base commit 248c649.

This pull request removes 1328 and adds 38 tests. Note that renamed tests count towards both.

github.com/lavanet/lava/v5/x/conflict ‑ TestGenesis
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestListConflictVote
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestListConflictVote/ByKey
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestListConflictVote/ByOffset
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestListConflictVote/Total
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestShowConflictVote
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestShowConflictVote/found
github.com/lavanet/lava/v5/x/conflict/client/cli ‑ TestShowConflictVote/not_found
github.com/lavanet/lava/v5/x/conflict/keeper ‑ TestCommit
github.com/lavanet/lava/v5/x/conflict/keeper ‑ TestCommit/BadVoteID
…

github.com/lavanet/lava/v5/protocol/chainlib ‑ TestAddAttributeToError/Valid_conversion
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestConvertToJsonError/valid_json
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestMatchSpecApiByName/test1
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestMatchSpecApiByName/test2
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestMatchSpecApiByName/test3
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestParsingRequestedBlocksHeadersRest
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestParsingRequestedBlocksHeadersRest/no_metadata
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestParsingRequestedBlocksHeadersRest/with-metadata
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestRegexParsing
github.com/lavanet/lava/v5/protocol/chainlib ‑ TestRestChainParser_NilGuard
…