[kaluli123123]

Summary

• Look up pending choices across the attached root session and its descendants, preserving cross-session isolation without changing the protocol.

Closes #175.

Root cause

Child observers inherit root subscribers, but choice answers previously searched only attached_thread_id and silently lost child answers.

Test plan and evidence

• RED before repair: Both routing regressions timed out waiting for the actual HTTP response URL before the repair.
• Focused: rap_callback_flow: 4 passed, including 2 new root/child connection routing regressions.
• Runtime: Actual cargo-run callback/client/HTTP smoke POSTed root-choice selected=0, first-child-choice selected=1, second-child-choice selected=0 from both connection types; foreign-session choices were not POSTed.
• Rust formatting, workspace Clippy with warnings denied, and all-target compilation passed through ./check.bash.
• cargo test --locked --all-targets --no-fail-fast: 357 passed, 7 failed, 0 ignored. The exact same seven snapshot failures independently reproduced on clean base 1abc6fcff1f186124f924b56aa92c3a3684c90c5 (355 passed, 7 failed, 0 ignored), across tui_reflow_snapshots (6) and tui_submit_wrap_snapshots (1). No snapshots or thresholds were changed.
• cargo test --locked --doc: 45 passed, 1 ignored.
• Independent read-only review: no blocking findings.

Changed files

• crates/infinity-daemon/src/client_handler.rs
• crates/infinity-daemon/src/memory_store.rs
• crates/infinity-daemon/tests/rap_callback_flow.rs
• docs/docs/infinity-code/rap-servers.md
• crates/infinity-daemon/CHANGELOG.md

Remaining gates

Draft: required full checks are not green. Remote CI and maintainer review remain outstanding. Docs/UI Prettier were skipped by the repository script because node_modules are absent; optional browser e2e and THIRD-PARTY verification were not reached after the test gate failed. No live model account was used.

One independent commit from base 1abc6fcff1f186124f924b56aa92c3a3684c90c5. No dependency or wire-protocol changes. No merge, deployment, or Issue closure performed.