ADR-027 resolves the architectural gap surfaced when ACME integration
became a concrete target:
1. TlsIdentity::Acme variant — static config data (domains, cache_dir,
directory, contact) with async AcmeState constructed at endpoint
setup via two-phase TlsSetup (not stuffed into the Clone-able enum).
2. TlsIdentity::RawKey decoupled from the iroh feature — uses
Ed25519SecretKey (alknet-core-owned wrapper over ed25519_dalek)
instead of iroh::SecretKey. Raw-key TLS identity (RFC 7250, the
default for most alknet nodes) now works in quinn-only builds.
iroh transport converts via SecretKey::from_bytes.
3. ACME feature-gated behind new acme feature (rustls-acme optional
dep). Non-ACME builds don't compile it.
4. dispatch_quinn guard for acme-tls/1 challenge connections — TLS-ALPN-01
is handled at the rustls cert resolver layer during the handshake;
the guard closes challenge connections gracefully instead of logging
a misleading "no handler" warning.
Research confirmed QUIC (quinn) handles ACME challenges differently than
TCP (reverse-proxy): quinn gives no ClientHello peek hook, but the
challenge is fully answered at the cert resolution step before the
connection surfaces to the application. No handler registration needed.
Spec updates: config.md, endpoint.md, open-questions.md (OQ-12),
overview.md + README.md (ADR index), ADR-010 (cross-ref).
Tasks: core/rawkey-decouple-from-iroh (gen 1, no deps),
core/acme-integration (gen 2, depends on rawkey). Graph: 36 tasks.