Extract PRISM share submission

[kiwidream]

Position in the stack

PR 5 of 9. Base: prism-block-candidate-submission. Depends on PR 76. Next: PR 78.

Review this PR against its configured base. See the stack guide for the complete order.

Why this slice exists

Stratum submit handling combines parsing, job/tip classification, duplicate identity, difficulty checks, durable share acceptance, and block-candidate routing. Moving those decisions into a dedicated service makes the acknowledgement boundary and rejection reasons testable without coordinator-wide state.

What changes

• Move submit parsing, context classification, rejection decisions, durable share routing, and block-candidate routing into share_submission.
• Introduce ShareSubmissionService with explicit ports for jobs, rejection, ledger append, and candidate enqueue.
• Preserve current-tip, retained-job, stale, stale-grace, duplicate, low-difficulty, normal-share, and block-candidate outcomes.
• Replace the unbounded/coarse-reset duplicate set with a thread-safe RecentShareIndex capped at 50,000 entries.
• Keep coordinator entry points as lazy initialization and thin delegation.

Reading the diff

The roughly 970 additions and 310 deletions consist of the new service, a direct 244-line owner test suite, and coordinator rewiring. The decision logic is relocated rather than duplicated. Review the pure parser/classifier helpers first, then the service acknowledgement path, duplicate index, ports, and coordinator delegate.

Intentional bounded change

At capacity, duplicate tracking now evicts the oldest entries instead of clearing the entire set. This bounds memory while avoiding the large retry-safety gap created by an all-at-once reset. Duplicate identity still uses immutable job worker and header information.

Validation

• 120 focused submission, vardiff, and candidate tests passed at this boundary.
• Share acknowledgement, rejection reason, stale-grace, duplicate, and candidate regressions pass in cumulative PRISM discovery.
• git diff --check passed.

Operator impact

No schema or configuration action is introduced by this slice.

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Note

Medium Risk
Touches the mining hot path (ack/reject, stale-grace, ledger append, block-candidate routing); behavior is intended to be preserved but duplicate-window eviction changed from full clear to LRU-style eviction at capacity.

Overview
Stratum submit handling moves out of PrismCoordinator into new lab/prism/share_submission.py. handle_submit becomes a one-line delegate to lazily built ShareSubmissionService, which wires coordinator behavior through explicit ports (reject, control snapshot, ledger, share writer, block-candidate enqueue, etc.).

Pure helpers (parse_submit_request, validate_submit_request, classify_submit_context, classify_submit_work) own wire parsing, job/tip/stale-grace classification, difficulty routing, and share vs async vs synchronous block paths—same rejection reasons and outcomes as before, now unit-tested in tests/test_prism_share_submission.py.

Duplicate detection shifts from coordinator _recent_share_lock + a set that cleared entirely past 50k entries to RecentShareIndex: thread-safe, insertion-ordered, 50k cap with oldest-entry eviction. Reserve/release go through the service; recent_share_keys is a compatibility descriptor over the index.

Share-related rejection string constants are centralized in share_submission and re-imported by the coordinator.

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