docs(architecture): add alknet-call crate spec, ADR-012, resolve OQ-07

Add architecture specs for the alknet-call crate:

- call-protocol.md: CallAdapter, EventEnvelope wire format, bidirectional
  stream model with ID-based correlation, PendingRequestMap, protocol
  operations (call/subscribe/batch/schema), per-request identity resolution,
  connection/stream lifecycle, error codes

- operation-registry.md: OperationSpec, async Handler type, OperationRegistry,
  AccessControl with trusted call bypass, OperationEnv with context
  propagation (parent_request_id, identity inheritance), service discovery,
  irpc integration layering, naming convention (no leading slash in names)

- ADR-012: Call protocol uses bidirectional QUIC streams with EventEnvelope
  framing and ID-based correlation. Protocol is stream-agnostic and symmetric.
  Resolves OQ-07.

Key design decisions:
- Handler type is async (Fn returning Pin<Box<dyn Future>>)
- OperationEnv::invoke propagates parent context (identity, metadata,
  parent_request_id)
- Identity resolution is per-request, not per-connection
- Operation names without leading slash (fs/readFile, not /fs/readFile)
- Batch is a client-side pattern, not a protocol primitive (OQ-14)
- Phase 1 uses service/op paths, node prefix added later (OQ-13)

Also: promote ADR-010 and ADR-011 from Proposed to Accepted, add OQ-13
and OQ-14 to open-questions.md.

docs/architecture/crates/call/README.md

@@ -0,0 +1,46 @@
+---
+status: draft
+last_updated: 2026-06-17
+---
+
+# alknet-call
+
+Structured RPC over QUIC: operations, request/response, streaming subscriptions, and service discovery. Implements `ProtocolHandler` on ALPN `alknet/call`.
+
+## Documents
+
+| Document | Status | Description |
+|----------|--------|-------------|
+| [call-protocol.md](call-protocol.md) | draft | CallAdapter, EventEnvelope framing, stream model, PendingRequestMap, bidirectional calls |
+| [operation-registry.md](operation-registry.md) | draft | OperationSpec, Handler, OperationRegistry, AccessControl, service discovery, irpc integration |
+
+## Applicable ADRs
+
+| ADR | Title | Relevance |
+|-----|-------|-----------|
+| [001](../../decisions/001-alpn-protocol-dispatch.md) | ALPN-Based Protocol Dispatch | CallAdapter registers on ALPN `alknet/call` |
+| [002](../../decisions/002-protocol-handler-trait.md) | ProtocolHandler Trait | CallAdapter implements ProtocolHandler |
+| [003](../../decisions/003-crate-decomposition.md) | Crate Decomposition | alknet-call depends on alknet-core and irpc |
+| [004](../../decisions/004-auth-as-shared-core.md) | Auth as Shared Core | AuthContext passed to call handlers |
+| [005](../../decisions/005-irpc-as-call-protocol-foundation.md) | irpc as Call Protocol Foundation | irpc provides framing and service dispatch |
+| [006](../../decisions/006-alpn-convention-and-connection-model.md) | ALPN String Convention | `alknet/call` ALPN, one ALPN per connection |
+| [007](../../decisions/007-bistream-type-definition.md) | BiStream Type Definition | CallAdapter receives Connection, not BiStream |
+| [008](../../decisions/008-secret-service-integration.md) | Vault Integration Point | Vault operations exposed via call protocol |
+| [012](../../decisions/012-call-protocol-stream-model.md) | Call Protocol Stream Model | Bidirectional streams, EventEnvelope, ID-based correlation |
+
+## Relevant Open Questions
+
+| OQ | Title | Status | Relevance |
+|----|-------|--------|-----------|
+| OQ-07 | Call protocol scope within a connection | resolved (ADR-012) | Stream model, multiplexing, scope |
+| OQ-13 | Operation path format and routing scope | open | Namespace paths: `/{service}/{op}` vs `/{node}/{service}/{op}` |
+| OQ-14 | Batch operation semantics | open | Whether batch is a protocol primitive or client-side pattern |
+
+## Key Design Principles
+
+1. **One connection, full access**: An `alknet/call` connection gives access to the entire operation registry — calls, subscriptions, batch, schema.
+2. **Protocol is symmetric**: Both sides can initiate calls. The server calling a client uses the same EventEnvelope format and correlation.
+3. **Stream-agnostic correlation**: PendingRequestMap correlates by request ID, not by stream. The protocol works with any stream arrangement.
+4. **Operation registry is dynamic**: Operations are registered at startup by the CLI binary. The registry supports JSON Schema discovery.
+5. **irpc is one dispatch backend**: Local operations dispatch directly. irpc service calls (vault, auth) are internal. The call protocol is the external interface.
+6. **Phase 1 is local dispatch only**: The operation registry dispatches to local handlers. Remote dispatch (head/worker routing) and irpc service dispatch are contracted but not built yet.