fix: bounded startup job recovery (trasser-recovery-paging)

Beads trasser-recovery-paging. Stacked on !70 (merged). Replace unbounded SELECT of all job bodies with keyset pages of 64 primary keys and one body read at a time. Preserve recovery states and terminal history. Regression: 137 jobs, 3 pages, idempotence; RED before fix, GREEN after. Java 27/27 PASS, docs 1135/1135, catalogue 230 valid, diff-check PASS. Not a hard single-body limit or speed claim: more SQL round trips. Single-service startup only; PostgreSQL/stand/crash testing and human acceptance remain open. No auto-merge.