docs: replace alkvault scaffold with alkcall project conventions
- AGENTS.md: full rewrite for the call+channels RPC crate (async/tokio,
vendored core types, alktype dep, producer/consumer framing, the two
stable wire formats, no-env-vars invariant, OperationEnv trait, abort
cascade, AccessControl peer auth, ADR index for both halves)
- implementation-specialist.md: replace vault crypto conventions (OsRng,
zeroize, AES-GCM) with 15 alkcall protocol conventions matching AGENTS.md
- docs/sdd_process.md: fix alkvault -> alkcall reference
Verification: no code changed (docs-only)
commit 0a031cd..HEAD
glm-5.2
a779dd0d0d