[LIghtJUNction]

Motivation

• Prevent unbounded durable growth of inbox_receipts caused by arbitrary fresh Ed25519 identities which can exhaust SQLite and degrade availability.

Description

• Add global and per-post receipt caps by introducing MAX_RECEIPTS_PER_POST and MAX_RECEIPTS_TOTAL in src/msgd/exchange.py and enforce them when inserting a new receipt, returning a StoreError with a 507 status on capacity exhaustion.
• Only apply the new limits on new INSERT operations so updates to existing receipts continue to work after capacity is reached.
• Add a regression test test_ack_receipts_enforce_per_post_and_global_capacity in tests/test_msgd.py which patches the limits and verifies per-post rejection, global rejection, and that updating an existing receipt still succeeds.

Testing

• Ran the focused exchange tests with uv run python -m unittest tests.test_msgd.ExchangeProtocolCase.test_ack_receipts_enforce_per_post_and_global_capacity tests.test_msgd.ExchangeProtocolCase.test_public_ack_receipts_are_unique_signed_reads and they passed.
• Ran the full test discovery with uv run python -m unittest discover -s tests and the suite completed successfully (146 tests passed, 1 skipped).
• Ran style checks with uv run ruff check src/msgd/exchange.py tests/test_msgd.py and uv run ruff format --check src/msgd/exchange.py tests/test_msgd.py, both of which succeeded.

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Codex Review Summary

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Review	Status	Commit	Review trigger
🔒 Security Review	✅ Completed 2026-09-28T11:51:43.797746Z	70430a4	PR opened

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[LIghtJUNction]

已被 #143 取代，关闭。旧补丁打在已删除的 src/msgd 上；现行 src/msg 的对应容量上限在分支 fix/capacity-recovery-20260928（head e77b53b），该分支已包含合并后的 #142。