tasks: decompose vault, core, call crates into 28 atomic implementation tasks

Break down the three initial crates (alknet-vault, alknet-core, alknet-call)
into dependency-ordered task files for implementation agents.

Structure:
- tasks/vault/ (10 tasks) — drift fixes from ADR-025/026 refactor, review,
  spec sync. Vault is independent and can run fully in parallel with core/call.
- tasks/core/ (6 tasks) — crate init, core types, config, auth, endpoint,
  review. Core is foundational; call depends on it.
- tasks/call/ (12 tasks) — split into registry/ and protocol/ topic subdirs
  reflecting the two subsystems. CallAdapter is the merge point.

Key decisions:
- Drifts 3+9+10 grouped as one task (key-versioning-rotation) — the complete
  ADR-021 rotation feature that doesn't compile in pieces
- Reviews injected at end of each crate phase (vault, core, call)
- Vault spec-sync task removes the drift table and bumps doc status to stable
- ACME deferred in core/endpoint (noted as TODO; X509 manual certs for now)
- OperationEnv kept as a trait (load-bearing for ADR-024 layering)

Validated: 28 tasks, no cycles, 11 generations of parallel work.
Critical path runs through call (11 tasks). Vault completes by generation 4.
6 high-risk tasks identified (21%): irpc-removal, endpoint, operation-context,
operation-env, call-adapter, abort-cascade.

tasks/core/config.md

@@ -0,0 +1,190 @@
+---
+id: core/config
+name: Implement StaticConfig, DynamicConfig, AuthPolicy, ApiKeyEntry, ConfigReloadHandle, TlsIdentity
+status: pending
+depends_on: [core/core-types]
+scope: moderate
+risk: low
+impact: component
+level: implementation
+---
+
+## Description
+
+Implement the configuration types in `src/config.rs`. These are the config
+structures consumed by the endpoint and the CLI binary. StaticConfig is
+immutable at startup; DynamicConfig is hot-reloadable via ArcSwap.
+
+### StaticConfig
+
+```rust
+pub struct StaticConfig {
+    pub listen_addr: Option<SocketAddr>,
+    pub tls_identity: Option<TlsIdentity>,
+    pub iroh_relay: Option<RelayUrl>,
+    pub drain_timeout: Duration,
+}
+```
+
+Immutable configuration resolved at startup. `listen_addr` is None for
+iroh-only nodes. `tls_identity` is required if `listen_addr` is Some.
+
+### TlsIdentity
+
+```rust
+pub enum TlsIdentity {
+    X509 { cert: PathBuf, key: PathBuf },
+    RawKey(iroh::SecretKey),
+    SelfSigned,
+}
+```
+
+Three modes (OQ-12):
+- `X509`: domain certificate for browser/WebTransport clients
+- `RawKey`: RFC 7250 raw Ed25519 public key — default for P2P, no domain/CA
+- `SelfSigned`: development only
+
+`RawKey` uses `iroh::SecretKey` (Ed25519) — re-exported from iroh, which
+alknet-core depends on (feature-gated). The key can be derived from
+alknet-vault at the assembly layer or generated fresh.
+
+### DynamicConfig
+
+```rust
+#[derive(Debug, Clone)]
+pub struct DynamicConfig {
+    pub auth: AuthPolicy,
+    pub rate_limits: RateLimitConfig,
+}
+```
+
+Runtime-reloadable via ArcSwap.
+
+### AuthPolicy
+
+```rust
+pub struct AuthPolicy {
+    pub authorized_fingerprints: HashSet<String>,
+    pub api_keys: Vec<ApiKeyEntry>,
+}
+```
+
+Fingerprints stored as strings (no russh dependency in core — ADR-003).
+Certificate authority entries deferred to alknet-ssh (omitted from v1 to avoid
+referencing an undefined type; adding back is additive).
+
+### ApiKeyEntry
+
+```rust
+pub struct ApiKeyEntry {
+    pub prefix: String,
+    pub hash: String,
+    pub scopes: Vec<String>,
+    pub description: String,
+    pub expires_at: Option<u64>,
+}
+```
+
+Carries forward from reference implementation. Prefix (first 8 chars) for O(1)
+lookup, SHA-256 hash for verification.
+
+### RateLimitConfig
+
+```rust
+pub struct RateLimitConfig {
+    pub max_connections_per_ip: usize,
+    pub max_auth_attempts: usize,
+}
+```
+
+### ArcSwap pattern
+
+```rust
+let dynamic = Arc::new(ArcSwap::new(Arc::new(DynamicConfig::default())));
+```
+
+- Reads: `dynamic.load()` returns `Arc<DynamicConfig>` — lock-free
+- Writes: `dynamic.store(Arc::new(new_config))` — atomic swap
+- No locks: ArcSwap uses atomic operations
+
+### ConfigReloadHandle
+
+```rust
+pub struct ConfigReloadHandle {
+    dynamic: Arc<ArcSwap<DynamicConfig>>,
+}
+
+impl ConfigReloadHandle {
+    pub fn reload(&self, new_config: DynamicConfig);
+    pub fn dynamic(&self) -> Arc<DynamicConfig>;
+}
+```
+
+- `reload()`: atomically replaces the dynamic config
+- `dynamic()`: returns current config as `Arc<DynamicConfig>`
+
+**Config reload is a privilege-escalation path.** A reload that adds an
+authorized fingerprint or API key grants access immediately. The reload
+trigger must be authenticated/local-only (SIGHUP, file watch, or admin call
+protocol operation). The implementation must not ship a reload endpoint with
+no auth "for convenience."
+
+### ConfigError
+
+```rust
+pub enum ConfigError {
+    InvalidFlag { name: String },
+    KeyFileNotFound { path: String },
+    BindFailed(io::Error),
+    TlsConfig(io::Error),
+    IncompatibleOptions,
+}
+```
+
+### Defaults
+
+- `drain_timeout`: 2 seconds
+- `max_connections_per_ip`: implementation default (reference uses a reasonable value)
+- `max_auth_attempts`: implementation default
+- `DynamicConfig::default()`: empty auth policy, default rate limits
+
+### What NOT to include
+
+Per the spec, StaticConfig does NOT include: `host_key`, `host_key_algorithm`,
+`proxy_config`, `stealth`, `transport_mode`, `listeners`. These are removed in
+the new model (ALPN dispatch replaces them — see config.md Key Differences).
+
+## Acceptance Criteria
+
+- [ ] `StaticConfig` struct with all fields per config.md
+- [ ] `TlsIdentity` enum with X509, RawKey, SelfSigned variants
+- [ ] `DynamicConfig` struct with `auth` and `rate_limits` fields
+- [ ] `AuthPolicy` struct with `authorized_fingerprints` and `api_keys`
+- [ ] `ApiKeyEntry` struct with all 5 fields
+- [ ] `RateLimitConfig` struct with both fields
+- [ ] `ConfigReloadHandle` with `reload()` and `dynamic()` methods
+- [ ] `ConfigError` enum with all variants
+- [ ] `DynamicConfig` derives `Clone`, `Debug` (for ArcSwap)
+- [ ] Default values match config.md (drain_timeout = 2s, etc.)
+- [ ] No russh dependency (fingerprints as strings)
+- [ ] Unit tests for Default impls
+- [ ] Unit test: ConfigReloadHandle reload swaps config atomically
+- [ ] `cargo test -p alknet-core` succeeds
+- [ ] `cargo clippy -p alknet-core` succeeds with no warnings
+
+## References
+
+- docs/architecture/crates/core/config.md — all type definitions
+- docs/architecture/decisions/003-crate-decomposition.md — ADR-003 (no russh in core)
+- docs/architecture/decisions/010-alpn-router-and-endpoint.md — ADR-010 (no ListenerConfig)
+
+## Notes
+
+> Config reload is a privilege-escalation path — do not ship an unauthenticated
+> reload endpoint. The ArcSwap pattern carries forward from the reference
+> implementation. StaticConfig removes all SSH-centric fields (host_key,
+> stealth, transport_mode, listeners) — those are handler concerns now.
+
+## Summary
+
+> To be filled on completion