Setup repo: migrate architecture specs, code stubs, and tasks from alkhub_ts

Copy architecture docs, ADRs, storage domain specs, research, reviews,
and 56 storage architecture tasks from the alkhub_ts monorepo. Adapt for
standalone @alkdev/hub repo structure (src/ not packages/hub/).

Sanitize all sensitive information:
- Replace private IPs (10.0.0.1) with localhost defaults
- Remove internal server hostnames (dev1, ns528096)
- Replace /workspace/ private paths with npm package references
- Remove hardcoded credentials from examples
- Rewrite infrastructure.md without private network details

Add Deno project scaffolding: deno.json (pinned deps), .gitignore,
AGENTS.md, entry point. Migrate existing code stubs (crypto, config
types, logger) with updated import paths.

tasks/architecture/storage/document-accesslevel-authorization.md

@@ -0,0 +1,38 @@
+---
+id: document-accesslevel-authorization
+name: Document accessLevel Authorization and Identity Cross-References
+status: completed
+depends_on: []
+scope: narrow
+risk: trivial
+impact: isolated
+level: implementation
+---
+
+## Description
+
+Two documentation gaps in the identity domain:
+
+1. **S01**: Who can change `accounts.accessLevel`? Can a `user` self-promote? The assumed invariants for application-level access control are undocumented.
+
+2. **S06**: `identity.md:12` lists FK targets but omits `sessions.accountId`. Add it for completeness so the identity doc is a full reference.
+
+## Acceptance Criteria
+
+- [ ] `identity.md` documents authorization rules for `accessLevel` changes (e.g., only `admin` can promote, users cannot self-promote)
+- [ ] `identity.md` FK target list includes `sessions.accountId → accounts.id`
+- [ ] Rules are consistent with ADR-012 terminology
+
+## References
+
+- docs/reviews/storage-architecture-review-2026-04-21.md#S01
+- docs/reviews/storage-architecture-review-2026-04-21.md#S06
+- docs/architecture/storage/identity.md
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion