M5: reproduce did.bot missing delegation across restart #20

Tests stacked on product #1: https://tangled.org/notplants-bot.bsky.social/agent-orchestrator.habitat/pulls/1 . The real-server gate mints two fresh accounts, requires a precise 501 failure from the strict delegation requirement, then verifies both DID documents and authenticated operations before and after service restart, plus namespace isolation. b1 passed with fresh m5builder0903 credentials; first run caught an encoded-port Host bug in the probe, fixed without changing this test. Full did.bot-on-Habitat delivery is unavailable, not passed. Nix #43/#44 supplies the isolated fixture. Review exact product bf345981ebeca9fc14640ad08cd8a8c38897df6d / tests 7daaec5ef9d4339554a4cb5c432e9ed896bd2062.