[PLT-700] Add MaxTxSearchResults cap to tx_search and block_search

[amir-deris]

Summary

• Adds MaxTxSearchResults field to RPCConfig (default 10,000) with mapstructure tag max-tx-search-results
• Applies the cap in TxSearch and BlockSearch after sort and before pagination — preserving order_by correctness while bounding response size and pagination work
• Adds the field to DefaultRPCConfig(), ValidateBasic(), and the toml template
• Emits a debug log when the cap truncates results so operators can detect broad queries hitting the limit
• Context propagation from the HTTP request through to the KV scan loops (ctx.Done() checks) was already wired correctly; no changes needed there

API note

total_count now reflects the capped result set (min(matches, max-tx-search-results)), not the true match cardinality above the limit. Clients that need the full match count must use narrower queries or a dedicated indexer.

Files changed

• sei-tendermint/config/config.go — new field + default + validation
• sei-tendermint/config/toml.go — template entry
• sei-tendermint/internal/rpc/core/env.go — debug log helper for cap truncation
• sei-tendermint/internal/rpc/core/tx.go — cap applied in TxSearch
• sei-tendermint/internal/rpc/core/blocks.go — cap applied in BlockSearch
• sei-tendermint/internal/rpc/core/tx_test.go — unit tests
• sei-tendermint/internal/rpc/core/block_search_test.go — unit tests

Follow-up

The RPC-layer cap does not bound KV indexer memory/CPU: the indexer still materialises and RPC still sorts the full match set before truncation.

Test plan

• go test ./sei-tendermint/config/... ./sei-tendermint/internal/rpc/core/... -run 'TestRPCConfigValidateBasic|TestTxSearchCap|TestBlockSearchCap' passes
• Review default value (10,000) is appropriate for production nodes
• Confirm operators can set max-tx-search-results = 0 to disable the cap if needed

[cursor]

PR Summary

Medium Risk
Changes public RPC semantics for total_count on broad queries and still sorts full indexer results before truncation, so heavy queries can stress nodes until indexer-level limiting exists.

Overview
Adds max-tx-search-results to RPC config (default 10,000; 0 turns the cap off) with validation and config.toml wiring.

TxSearch and BlockSearch truncate the match list after sorting and before pagination, so order_by stays correct and total_count is the capped size, not the full indexer match count.

Unit tests cover post-sort truncation, disabled cap, and when matches are under the limit.

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[cursor]

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[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Jun 18, 2026, 10:35 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.14%. Comparing base (4f5889e) to head (6008230).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3608      +/-   ##
==========================================
- Coverage   59.02%   58.14%   -0.88%     
==========================================
  Files        2215     2141      -74     
  Lines      182521   173981    -8540     
==========================================
- Hits       107734   101167    -6567     
+ Misses      65091    63819    -1272     
+ Partials     9696     8995     -701     

Flag	Coverage Δ
sei-chain-pr	43.93% <100.00%> (?)
sei-db	70.41% <ø> (ø)
sei-db-state-db	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-tendermint/config/config.go	73.68% <100.00%> (+0.16%)	⬆️
sei-tendermint/config/toml.go	55.00% <ø> (ø)
sei-tendermint/internal/rpc/core/blocks.go	65.66% <100.00%> (+1.02%)	⬆️
sei-tendermint/internal/rpc/core/tx.go	68.49% <100.00%> (+3.70%)	⬆️

... and 74 files with indirect coverage changes

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