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- Amend ADR-015: mark Decision 3 and Assumption 6 as superseded by ADR-022;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- Amend ADR-004: note 'enrich/replace' AuthContext language superseded by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/crates/vault/README.md

@@ -1,6 +1,6 @@
 ---
 status: draft
-last_updated: 2026-06-19
+last_updated: 2026-06-22-19
 ---
 
 # alknet-vault
@@ -38,8 +38,10 @@ cross the network.
 | ADR | Title | Relevance |
 |-----|-------|-----------|
 | [003](../../decisions/003-crate-decomposition.md) | Crate Decomposition | alknet-vault's standalone position |
+| [006](../../decisions/006-alpn-convention-and-connection-model.md) | ALPN String Convention | ALPN versioning pattern for potential `alknet/vault/v2` |
 | [005](../../decisions/005-irpc-as-call-protocol-foundation.md) | irpc as Call Protocol Foundation | VaultProtocol uses irpc directly |
 | [008](../../decisions/008-secret-service-integration.md) | Vault Integration Point | CLI-embedded, capability source |
+| [010](../../decisions/010-alpn-router-and-endpoint.md) | ALPN Router and Endpoint | Ed25519 as default curve for TLS raw key identity |
 | [014](../../decisions/014-secret-material-flow-and-capability-injection.md) | Secret Material Flow and Capability Injection | Capabilities carry vault-derived material |
 | [018](../../decisions/018-vault-standalone-crate.md) | Vault as Standalone Crate | Zero alknet crate dependencies |
 | [019](../../decisions/019-vault-assembly-layer-only.md) | Vault Assembly-Layer-Only Access | The assembly layer is the sole caller |
@@ -101,6 +103,21 @@ the full list.
   depth measure, not the primary control — the primary control is that
   `DerivedKey` never crosses the call protocol wire (ADR-014).
 
+## Known Source Drift
+
+The vault crate carries over source from the POC. The following items are
+known divergences between the current source and the spec. All must be
+corrected during implementation sync. This table is the single source of
+truth for drift tracking — if an item is fixed in source, update this table.
+
+| # | Item | Current source behavior | Target behavior (per spec) | Source location | Spec reference |
+|---|------|------------------------|-----------------------------|-----------------|----------------|
+| 1 | IV generation | `rand::random()` | `OsRng` (CSPRNG) | `encryption.rs` L133 | [encryption.md → Security Constraints](encryption.md#security-constraints), [service.md → Security Constraints](service.md#security-constraints) |
+| 2 | RwLock `unwrap()` | `unwrap()` on every `RwLock` acquisition (L142, 161, 182, 191, 196, 227, 264, 307, 340, 367) | `unwrap_or_else(\|e\| e.into_inner())` for poisoned lock recovery | `service.rs` (see line numbers) | [service.md → Security Constraints](service.md#security-constraints) |
+| 3 | `CURRENT_KEY_VERSION` | `1` (HD-derived, but v1 is reserved for TS PBKDF2 legacy per ADR-020) | `2` (HD-derived, per ADR-020) | `encryption.rs` | [encryption.md → Key Versioning](encryption.md#key-versioning), [ADR-020](../../decisions/020-hd-derivation-for-encryption-keys.md) |
+| 4 | `spawn()` return value | Returns a fresh, unspawned `VaultServiceActor` as the second tuple element (the spawned actor is consumed by `run`) | Either drop the second return value (return only `Client<VaultProtocol>`) or restructure so the returned actor is the one that was spawned | `service.rs` `VaultServiceActor::spawn()` | [service.md → Actor Dispatch](service.md#actor-dispatch) |
+| 5 | `HashMap::clear` zeroization | `KeyCache::clear()` removes entries and relies on `CachedKey`'s `Drop` impl for zeroization | Verify `HashMap::clear()` actually drops values (it does, but worth a test) | `cache.rs` | [service.md → Security Constraints](service.md#security-constraints) |
+
 ## Public API
 
 The vault re-exports its primary types from the crate root: