docs: correct ecosystem dependency direction and add integration context

Architecture docs previously referenced the hub as the authoritative source
for call/identity specs. In reality, call protocol, identity, and access control
come from @alkdev/operations; call graph schemas from @alkdev/flowgraph; task
graph schemas from @alkdev/taskgraph; event transport from @alkdev/pubsub. The
hub is a consumer of @alkdev/storage, not the other way around.

Key changes:
- overview.md: add Ecosystem Integration section with dependency direction
  diagram, What Comes From Where table, repo layer bridging pattern, and
  circular dependency avoidance guidance
- overview.md: promote repo-layer vs operations-bridging from open question
  to explicit decision (CRUD in storage, bridging in consumer)
- overview.md: add zero-ecosystem-dependency statement; fix taskgraph type
  names (TaskGraphNodeAttributes, DependencyEdge)
- overview.md: fix terminology (hub is consumer, not authority)
- metagraph.md: add Ecosystem Context section; replace hub references with
  correct ecosystem sources; fix GraphStatus/GraphBaseType enum
  mischaracterization (C1); unify empty-array semantics with sqlite-host (C2);
  clarify repo layer does NOT import operations (C3); add flowgraph canonical
  schema note; add versioning cross-reference to graph_types table
- encrypted-data.md: reframe hub as provenance not authority; update What
  Lives Where table; fix standalone table advice; update references
- sqlite-host.md: fix actors table description; unify empty-array semantics;
  contextualize hub as reference consumer; add operations identity reference

docs/architecture/sqlite-host.md

@@ -62,9 +62,9 @@ All tables share these columns:
 }
 ```
 
-**Notable differences from hub's PostgreSQL common columns**:
+**Notable differences from a typical PostgreSQL common columns pattern**:
 
-| Column      | SQLite                                | PostgreSQL (hub)                                              |
+| Column      | SQLite                                | PostgreSQL (typical)                                         |
 | ----------- | ------------------------------------- | ------------------------------------------------------------- |
 | `id`        | text PK (consumer-generated)          | text PK with `$defaultFn(() => crypto.randomUUID())`          |
 | `metadata`  | `text` with JSON mode                 | `jsonb` with `$type<Record<string, unknown>>()`               |
@@ -130,12 +130,13 @@ Stores edge type definitions within a graph type.
 a graph type.
 
 **Empty array semantics**: `allowedSourceTypes` and `allowedTargetTypes` default
-to `[]` (empty JSON array) in the database. The repository layer must treat `[]`
-(empty array) as "no restriction" — any node type is a valid endpoint — matching
-the behavior of `undefined` in the `EdgeType` schema. A non-empty array
-restricts endpoints to only the listed node types. There is no "no types
-allowed" state; if edge types need to be disabled, use a status or soft-delete
-pattern on the edge type definition.
+to `[]` (empty JSON array) in the database. `[]` means "no restriction" — any
+node type is a valid endpoint — matching the behavior of `undefined` in the
+`EdgeType` schema layer. A non-empty array restricts endpoints to only the
+listed node types. There is no "no types allowed" state; if edge types need to
+be disabled, use a status or soft-delete pattern on the edge type definition.
+The repository layer must enforce this convention consistently. See
+[metagraph.md](./metagraph.md) for the schema-layer definition.
 
 ### `graphs`
 
@@ -209,9 +210,11 @@ its edges.
 
 ### `actors`
 
-Standalone identity table. Currently not referenced by any relation. This is a
-placeholder for the hub's account/identity model and may become a node type in
-an ACL graph or remain a standalone table. See [overview.md](./overview.md) Open
+Standalone identity table. Currently not referenced by any relation — the
+`actors` table has no FK references to or from any metagraph table and is not
+included in `relations.ts`. This is a placeholder for identity data and may
+become a node type in an ACL graph (based on `@alkdev/operations`'s `Identity`
+interface) or remain a standalone table. See [overview.md](./overview.md) Open
 Question 1.
 
 | Column    | Type                | Constraints                             | Notes              |
@@ -355,14 +358,15 @@ changes:
 | `integer` (boolean mode)         | `boolean`                                |
 | `text` (enum)                    | `pgEnum` or `text` with check constraint |
 
-See hub's `commonCols` reference in
-[../../hub/docs/architecture/storage/table-reference.md] for the PostgreSQL
-patterns.
+See a consumer's `commonCols` pattern (e.g., the hub's
+`/workspace/@alkdev/hub/docs/architecture/storage/table-reference.md`) for
+PostgreSQL reference patterns.
 
 ## References
 
 - Drizzle ORM SQLite core: https://orm.drizzle.team/docs/sqlite-core
 - libsql client: https://github.com/tursodatabase/libsql
-- Hub common columns pattern:
+- Hub common columns (reference consumer):
   `/workspace/@alkdev/hub/docs/architecture/storage/table-reference.md`
+- Operations AccessControl and Identity: `/workspace/@alkdev/operations/docs/architecture/api-surface.md`
 - Source: `src/sqlite/`