[P2] Prevent same-run PRD lease refresh from reviving released leases

[brAperia2025]

Context: CodeRabbit feedback on upstream PR coleam00#1875 surfaced a likely-valid DB race in our fork.

Problem:

• packages/core/src/db/prd-execution-leases.ts refreshes an existing same-run lease using WHERE id = $7.
• If another path releases the lease after the initial read, the refresh can update a released row back to active.

Impact:

• P2 race-condition correctness issue.

Acceptance criteria:

• Constrain the refresh UPDATE to unreleased rows, e.g. WHERE id = $7 AND released_at IS NULL.
• Keep rowCount checks and surface a clear error when no active row remains.
• Add a regression test for refresh after release/no-op update.

Reference:

• CodeRabbit comment: Merge AISRV Archon state model into dev coleam00/Archon#1875 (comment)