Route Mneme and Crucible replay contracts

[HarperZ9]

What changed

• declare crucible.replay-template/1 from Crucible to Mneme
• declare crucible.replay-pack/1 from Mneme to Crucible
• preserve the existing Mneme-to-Crucible thesis route
• remove the stale crucible.recheck-pack/1 alias
• enforce full built-in registry and shipped-manifest equality plus canonical content-hash parity

Why

Plexus routes capabilities by exact string. Mneme had replay capability names that Crucible/Plexus did not declare, leaving the new replay path orphaned even though the underlying CLIs existed.

Validation

• focused routing/grounding/manifest gate — 17 passed
• full suite — 60 passed
• both routes resolve as direct one-hop edges
• independent code review — PASS
• git diff --check — clean