feat: Document completed tasks for KMS, Cryptography, and Plugin Libraries

- Added detailed task completion records for KMS interface implementation and CLI support for file-based keys.
- Documented security enhancements including Argon2id password hashing, audit event contracts, and rate limiting configurations.
- Included scoped service support and integration updates for the Plugin platform, ensuring proper DI handling and testing coverage.

docs/technical/interfaces/README.md

@@ -0,0 +1,48 @@
+# Interfaces, Contracts & Schemas
+
+Specifications covering APIs, data contracts, event envelopes, and enforcement models.
+
+## External & Internal APIs
+- [../09_API_CLI_REFERENCE.md](../../09_API_CLI_REFERENCE.md) – canonical REST and CLI surface (scan, policy, auth, health).
+- [../api/policy.md](../../api/policy.md) – Policy Engine REST endpoints.
+- Module APIs: see relevant module architecture docs (e.g., [../../modules/export-center/api.md](../../modules/export-center/api.md)).
+
+## Policy & Decisioning
+- [../policy/overview.md](../../policy/overview.md) – Policy Engine fundamentals.
+- [../policy/dsl.md](../../policy/dsl.md) – `stella-dsl@1` grammar.
+- [../policy/lifecycle.md](../../policy/lifecycle.md) – creation, promotion, approval flows.
+- [../policy/runs.md](../../policy/runs.md) – execution orchestrations.
+- [../policy/exception-effects.md](../../policy/exception-effects.md) – waiver semantics.
+- [../policy/gateway.md](../../policy/gateway.md) – gateway service contract.
+- [../60_POLICY_TEMPLATES.md](../../60_POLICY_TEMPLATES.md) – YAML/Rego samples.
+
+## Data Schemas & Storage Contracts
+- [../11_DATA_SCHEMAS.md](../../11_DATA_SCHEMAS.md) – MongoDB/Redis/document shapes.
+- JSON schemas under [../schemas/](../../schemas/) – policy diff, explain trace, run request, run status, preview sample, report sample.
+- [../../modules/scanner/architecture.md](../../modules/scanner/architecture.md) – SBOM cache and scan job contracts.
+- [../../scanner-core-contracts.md](../../scanner-core-contracts.md) – shared scanner DTOs.
+
+## Events & Messaging
+- [../events/README.md](../../events/README.md) – event catalogue (`scanner.scan.completed@1`, `scheduler.rescan.delta@1`, etc.).
+- Payload schemas in [../events/*.json](../../events/) and samples in [../events/samples/](../../events/samples/).
+- [../observability/policy.md](../../observability/policy.md) and [../observability/ui-telemetry.md](../../observability/ui-telemetry.md) – telemetry event guidance.
+
+## Ingestion & Evidence Contracts
+- [../ingestion/aggregation-only-contract.md](../../ingestion/aggregation-only-contract.md) – Aggregation-Only Contract reference.
+- [../aoc/aoc-guardrails.md](../../aoc/aoc-guardrails.md) – guardrails checklist.
+- [../advisories/aggregation.md](../../advisories/aggregation.md) – advisory observation schema.
+- [../vex/aggregation.md](../../vex/aggregation.md) – VEX observation schema.
+- [../../modules/concelier/operations/connectors/](../../modules/concelier/operations/connectors/) – connector-specific payload notes.
+
+## Identity, Quota & Licence Enforcement
+- [../license-jwt-quota.md](../../license-jwt-quota.md) – offline quota token design.
+- [../30_QUOTA_ENFORCEMENT_FLOW1.md](../../30_QUOTA_ENFORCEMENT_FLOW1.md) – enforcement sequence diagram.
+- [../33_333_QUOTA_OVERVIEW.md](../../33_333_QUOTA_OVERVIEW.md) – free tier policy.
+- [../30_QUOTA_ENFORCEMENT_FLOW1.md](../../30_QUOTA_ENFORCEMENT_FLOW1.md) and [../33_333_QUOTA_OVERVIEW.md](../../33_333_QUOTA_OVERVIEW.md) – pair with [../29_LEGAL_FAQ_QUOTA.md](../../29_LEGAL_FAQ_QUOTA.md) for legal framing.
+- [../../modules/authority/architecture.md](../../modules/authority/architecture.md) – OpTok issuance & validation contracts.
+- [../../modules/registry/architecture.md](../../modules/registry/architecture.md) – token service scope and audit requirements.
+
+## Transparency & Attestation
+- [../../modules/attestor/architecture.md](../../modules/attestor/architecture.md) – DSSE/Rekor bundle contracts.
+- [../../modules/signer/architecture.md](../../modules/signer/architecture.md) – signing workflow contracts.
+- [../../modules/export-center/provenance-and-signing.md](../../modules/export-center/provenance-and-signing.md) – export bundle evidence artefacts.