[LIghtJUNction]

Motivation

• Engagement ranking could overfetch thousands of ranked IDs and materialize full post rows (including bodies) before slicing, enabling high-memory reads from unauthenticated requests.

Description

• Add Store.post_boards_by_ids to perform a lightweight SELECT id, board FROM posts WHERE id IN (...) lookup that avoids loading post bodies (new function in src/msgd/store.py).
• Update Handler._ranked_posts to resolve existence and per-board membership using the lightweight lookup, remove stale IDs from the ranking index as before, and only call posts_by_ids for the bounded set of selected IDs to be returned (changes in src/msgd/server.py).
• Add a regression test RankingMemoryCase.test_ranking_only_loads_bodies_for_returned_posts to tests/test_engagement.py which simulates a 100-ID ranking and asserts only the returned six posts are materialized.
• The change preserves existing stale-ID cleanup and board-filtering semantics while preventing large body materialization during ranking resolution.

Testing

• Ran the focused engagement test: PYTHONPATH=src uv run pytest tests/test_engagement.py -q, which reported 1 passed, 1 skipped (skip when VALKEY_TEST_URL is not configured).
• Ran full test suite with PYTHONPATH=src uv run pytest -q, which completed successfully with 145 passed, 1 skipped, 8 subtests passed.
• Ran style checks using uv run ruff check src/msgd/server.py src/msgd/store.py tests/test_engagement.py and git diff --check, both of which passed.

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Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
🔒 Security Review	✅ Completed 2026-09-28T11:48:11.824948Z	3487719	PR opened

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[LIghtJUNction]

关闭：现行 src/msg 中不存在 WebSub、持久 agent state、engagement ranking 或 mention 别名扇出，因此没有对应的无界路径可修。此关闭仅表示补丁不适用于现行代码，不代表生产已验收。