docs(architecture): resolve review #002 Tiers 1-3 — mechanical and consistency fixes

Governance (Tier 2):
- Advance ADR-022 and ADR-023 from Proposed to Accepted (specs already
  depend on their types as source of truth)
- Amend ADR-015: mark Decision 3 and Assumption 6 as superseded by ADR-022;
  update handler_identity type to CompositionAuthority
- Amend ADR-002: note handle() signature revised by ADR-007 (BiStream → Connection)
- Amend ADR-004: note 'enrich/replace' AuthContext language superseded by
  ADR-011's immutability model; update to describe set_identity on Connection
- Update main README ADR table to show ADR-022/023 as Accepted

Spec-ADR consistency (Tier 3):
- Add abort_policy: AbortPolicy field to OperationContext struct (ADR-016
  Decision 6 mandated this but the spec omitted it)
- Define AbortPolicy enum (AbortDependents | ContinueRunning) with Default impl
- Add abort_policy to build_root_context and LocalOperationEnv::invoke()
- Define the OperationEnv trait explicitly with invoke() and
  invoke_with_policy() methods (was referenced as 'must remain a trait'
  but never defined)
- Specify From<StreamError> for HandlerError impl with exact variant mapping
- Add Connection::from_quinn() / from_iroh() constructors (was referenced
  as Connection::new() but never defined)
- Remove undefined CertAuthorityEntry placeholder from AuthPolicy v1 (will
  be added additively when alknet-ssh lands)
- Fix config.md key-differences table: rate limits are in DynamicConfig,
  not StaticConfig

Mechanical fixes (Tier 1):
- overview.md: 'closes the QUIC stream' → 'closes the connection' (stale
  from pre-ADR-007 model)
- overview.md: OQ-04 entry updated from stale 'defer to implementation'
  to 'resolved: static at startup'
- mnemonic-derivation.md: remove duplicate helper functions block (incomplete
  first copy, complete second copy)
- ADR-003: add iroh (feature-gated) to alknet-core dependency list, added
  by ADR-010
- ADR-021: fix ambiguous 'W1 drift issue from the vault review' cross-reference
- ADR-022: rephrase FromCall 'leaf locally' to 'leaf in the local registry'
- ADR-017: add error_schemas to from_call mirror list and services/schema
  step (inconsistency with ADR-023)
- ADR-016: fix self-referential citation ('ADR-016 Assumption 5' → 'Assumption 5')
- Add ScopedOperationEnv::empty(), allows(), new() and
  CompositionAuthority::none(), new() impl blocks (referenced but undefined)
- Add call.completed clarification for non-subscription calls
- Add services/schema leading-slash normalization note
- Crate README ADR tables: add missing ADR-013 (call), ADR-015 (core),
  ADR-006 + ADR-010 (vault)
- Vault README: add consolidated 'Known Source Drift' table tracking all
  four drift items (OsRng, unwrap, CURRENT_KEY_VERSION, spawn bug) in one
  place, including the two previously missing from README

docs/architecture/decisions/022-handler-registration-provenance-and-composition-authority.md

@@ -2,7 +2,7 @@
 
 ## Status
 
-Proposed
+Accepted
 
 ## Context
 
@@ -120,7 +120,8 @@ pub enum OperationProvenance {
     FromOpenAPI,
     /// MCP forwarding stub (from_mcp), leaf — cannot compose.
     FromMCP,
-    /// QUIC forwarding stub (from_call), leaf locally — cannot compose.
+    /// QUIC forwarding stub (from_call). Leaf in the local registry —
+    /// forwards calls to a remote node; cannot compose locally.
     FromCall,
     /// JSON Schema definition (from_jsonschema), no handler — schema only.
     FromJsonSchema,
@@ -134,7 +135,7 @@ pub enum OperationProvenance {
 | `Local` | Yes | Yes — scopes set by assembly layer | External or Internal (assembly declares) | Trusted code |
 | `FromOpenAPI` | No (leaf) | No | Internal | HTTP endpoint trusted; handler is a forwarding stub |
 | `FromMCP` | No (leaf) | No | Internal | MCP server trusted; handler is a forwarding stub |
-| `FromCall` | No (leaf locally) | No | Internal | Remote node trusted; handler is a forwarding stub |
+| `FromCall` | No (leaf in local registry) | No | Internal | Remote node trusted; handler is a forwarding stub |
 | `FromJsonSchema` | N/A (no handler) | No | N/A | N/A |
 | `Session` | Yes (within sandbox) | Yes — scopes set by assembly layer at sandbox creation | Internal always | Untrusted code in sandbox |
 
@@ -178,6 +179,24 @@ pub struct CompositionAuthority {
     /// handler can reach in composition.
     pub resources: HashMap<String, Vec<String>>,
 }
+
+impl CompositionAuthority {
+    /// `None` — for leaves that don't compose (convenience for
+    /// `composition_authority: CompositionAuthority::none()`).
+    pub fn none() -> Option<Self> { None }
+
+    /// Construct a composition authority with the given label and scopes.
+    pub fn new(
+        label: &str,
+        scopes: impl IntoIterator<Item = String>,
+    ) -> Self {
+        Self {
+            label: label.to_string(),
+            scopes: scopes.into_iter().collect(),
+            resources: HashMap::new(),
+        }
+    }
+}
 ```
 
 This supersedes ADR-015's Assumption 6. ADR-015's core decision (authority
@@ -212,6 +231,23 @@ pub struct ScopedOperationEnv {
     /// parameterized-dispatch attack surface.
     pub allowed_operations: HashSet<String>,
 }
+
+impl ScopedOperationEnv {
+    /// Empty set — for leaves that don't compose (no reachable operations).
+    pub fn empty() -> Self {
+        Self { allowed_operations: HashSet::new() }
+    }
+
+    /// Construct from an iterable of operation names.
+    pub fn new(ops: impl IntoIterator<Item = String>) -> Self {
+        Self { allowed_operations: ops.into_iter().collect() }
+    }
+
+    /// Returns true if the given operation name is reachable.
+    pub fn allows(&self, name: &str) -> bool {
+        self.allowed_operations.contains(name)
+    }
+}
 ```
 
 ### 4. The registration bundle carries all three