fix(document): avoid premature partial search on missing RPC responses

[Faolain]

Links:

• Flake investigation log + context: test(document): de-flake redundancy search test (ci:part2) #8

What this does:

• When distributed search encounters missing RPC shard responses, the iterator can prematurely conclude it is done, causing silent short-reads (the ci:part2 flake signature: "Failed to collect all messages X < Y. Log lengths: [...]").
• This change surfaces missing shard info on MissingResponsesError and prevents the search iterator from marking itself done when missing responses occurred during a fetch.

Changes:

• packages/programs/data/document/document/src/search.ts
  • Align remote.timeout with remote.wait.timeout (if wait provided and remote.timeout not set)
  • Expose onMissingResponses hook internally and ensure missing responses keep the iterator open (unsetDone + hasMore=true)
• packages/programs/rpc/src/utils.ts
  • MissingResponsesError now carries missingGroups metadata
• packages/programs/rpc/test/index.spec.ts
  • Adds a narrow regression test for missingGroups

Local verification:

• PASS: pnpm --filter @peerbit/rpc test -- --grep "reports missing groups on timeout"
• PASS: (stress) for i in {1..25}; do PEERBIT_TEST_SESSION=mock pnpm --filter @peerbit/document test -- --grep "can search while keeping minimum amount of replicas" || break; done
  • 25/25 passed locally on this branch.

[Faolain]

AI Review (and yelling at me for asking it to repeat tests)