v1.0.4

v1.0.4: pre-launch foundation cleanup.

Six findings from the post-v1.0.3 contract review, plus the
contract review's deliverables (overlay banner, Standing Rules,
CONTRACT-review-findings.md, v1.1-plan.md) which merged
separately. v1.0.4 absorbs the findings and lands the
documentation continuity that makes the contract review's
output visible from CONTRACT.md alone.

Findings:

1. graph.relations(source=, target=, type=) added as the
   canonical form. graph.get_relations() kept as backward-
   compatible alias.

2. Per-error-page footers pointing at runtime.errors /
   BehaviorFailure observation surfaces added to 10 error pages
   that route through behavior.failed.

3. WARNING-log vs BehaviorFailure field-name divergence
   documented in failure-model.md.

4. Boundary-anchored test added for _requeue_unfired's zero-
   subscriber case, per Standing Rule §2.

5. Review-overlay markers added at three CONTRACT prose sites
   (v0 #11, v0 #16, v0.8 #19) clarifying scope without modifying
   amendment prose.

6. v1.0.2.post1 amendment section appended retroactively,

   completing the archeological record per Standing Rule §1.

Two v1.1 candidates surfaced during v1.0.4 work and filed in
v1.1-plan.md: C-3 (failure-routing convention for programmer-
error classes that currently escape behavior.failed) and I-4
(replay-divergence-error doc cross-link, parked behind C-3).

This is the last patch release before public launch.

See CHANGELOG.md for full notes.