refactor(bayn): remove dormant candidate tooling

[gregkonush]

Summary

• remove the dormant candidate-development tree, historical executable payloads, and scheduled qualification/paper-activation workflows
• retain one compact immutable ledger for every Candidate 1-25 terminal ordinal and the strongest preserved receipt identities
• reduce the production image to the Bayn service and forward-performance entrypoints with no Bun, Git, audit, or collector runtime tooling
• keep runtime qualification decoding, pure statistics/economic decisions, PAPER execution, broker, risk, accounting, reconciliation, and forward-performance code

Stacked on #13611.

Related Issues

None

Testing

• bun run --filter @proompteng/bayn test — 1053 passed, 160 PostgreSQL-environment skips, 0 failed
• bun run --filter @proompteng/bayn tsc
• bun run --filter @proompteng/bayn lint:effect
• bun run --filter @proompteng/bayn build
• bun run --filter @proompteng/bayn lint:oxlint
• bun run --filter @proompteng/bayn lint
• bun test packages/scripts/src/bayn — 126 passed, 0 failed
• nix-instantiate --parse nix/images/bayn.nix
• git diff --check
• hosted full Bayn, PostgreSQL, amd64/arm64 image, dependency, broker, Effect runtime, release, and repository gates are green

Breaking Changes

The retired local candidate-development, qualification audit/collector, hourly qualification, and artifact-driven activation entrypoints are removed. Runtime compatibility and trading safety paths remain.

Checklist

• Testing section documents the exact validation performed.
• Screenshots are not applicable; Breaking Changes are documented.
• Documentation and compact terminal history are updated.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

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[gregkonush]