fix(api): isolate queue reads from archive load

[tom-sapletta-com]

Ticket: PLF-10675
Correlation ID: planfile-workload-isolation

Outcome

• route full, operational, summary, and heavy archive cache builds through separate striped lock pools
• reserve lightweight status and filtered queue reads from archive-export lock contention
• bound simultaneous heavy archive projections to four builds
• retain per-query miss coalescing and existing cache semantics

Evidence

• 404 passed, 6 skipped
• focused regressions prove a blocked archive build does not block summary or filtered operational reads
• 12-way archive concurrency test proves the maximum active heavy-build count is four
• ruff check, compileall, and git diff --check pass
• production baseline after PR fix(api): bound indexed queue read amplification #44: 45/50 requests completed within 5 seconds; the remaining 2 status and 3 archive timeouts motivated this isolation

Authority

Bounded local/runtime repair for PLF-10675. Exact-head Validator approval and protected merge are required.

[ifuri-validator-agent]

Deterministic Validator approval for exact head 20da4a9f38c3611d4ad67f80634f867069b1ad4f.

Ticket: PLF-10675
Correlation ID: planfile-pr-45-PLF-10675
Model: zai/glm-5.3
Reviewed diff chunks: 1
Advisory LLM verdict: APPROVE
Advisory summary: Reviewed all 1 diff chunk(s). The change partitions ticket-list build locks into per-workload pools and adds a bounded semaphore (4 slots) for heavy archive-operational builds, preventing archive exports from starving summary and filtered queue reads. Cache semantics and per-query miss coalescing are retained. Tests cover non-blocking behavior under a stalled heavy build and bounded concurrency (max 4 of 12). CI checks pass.
Advisory findings: none
The LLM output above is advisory and was not used as the approval trust root.
Merge will be attempted after this approval when explicitly authorized.

Decision record (recomputable)

DECISION D-675-5829
TICKET PLF-10675
HEAD_SHA 20da4a9f38c3611d4ad67f80634f867069b1ad4f
CORRELATION_ID planfile-pr-45-PLF-10675
ACTOR agent:ifuri-validator-agent[bot]
APPLIED_RULE P-CORE-015
INPUT author_login = "tom-sapletta-com"
INPUT observed_checks = ["notify=PASS","ci-loop=PASS"]
INPUT required_checks = ["ci-loop","notify"]
INPUT required_checks_source = "protected registry (env/request)"
INPUT reviewer_login = "ifuri-validator-agent[bot]"
INPUT superseded_checks = []
VERDICT APPROVE AUTHORITY DETERMINISTIC
REJECTED REQUEST_CHANGES BECAUSE NO_UNSAFE_CHANGE_REASON_FOUND
ADVISORY llm_verdict = "APPROVE" MODEL "zai/glm-5.3"
ASSERT VERDICT_AUTHORITY != "ADVISORY"