epic-12: finish by writing epic-5-resolution.md

docs/epics/epic-5-resolution.md

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+# Epic 5 — Approval system (Tiers, grants, approvals)
+
+## completed deliverables
+
+### 1. Tier model (T0-T4)
+
+introduced `Tier` as a enum in `core:events` with values 0-4 where 0 is inference and 4 is something destructive.
+
+---
+
+### 2. grants system
+
+introduced `ApprovalGrant` as a serializable data class in `core:approvals`.
+
+scopes:
+
+```text
+Session -> stage -> project
+```
+
+properties:
+
+* all grants work on the concrete scope.
+* grants are revoked when scope changes.
+* grants contain set of `permittedTiers`.
+
+---
+
+### 3. approval lifecycle events
+
+introduced events in `:core:events` to emit when approval is:
+- ApprovalRequested
+- ApprovalDecisionResolved
+- ApprovalGrantCreated
+- ApprovalGrantExpired
+
+---
+
+### 4. timeout semantics
+
+timeout are resolved on a higher level, not in approval system.
+
+---
+
+### 5. steering injection module
+
+introduced `UserSteering` in `core:events`.
+gets injected in approval and should be respected by other components.
+
+---
+
+# final state
+
+Correx now has:
+
+> tiered, replay-safe approval authorization layer