Add external review overview for Phase C1

Author: iamfurydammit

REVIEW-OVERVIEW.md

@@ -0,0 +1,86 @@
+# XSTRP — External Review Overview (Phase C1)
+
+## Purpose of This Review
+
+XSTRP (XRP Safe Transfer & Recovery Protocol) Phase C1 defines a **minimal, frozen protocol core**
+for safe, recoverable asset transfers under adversarial conditions.
+
+This review seeks feedback on:
+- Logical correctness
+- State machine safety
+- Failure handling
+- Protocol invariants
+- Threat model alignment
+
+This review does NOT seek feedback on:
+- Cryptographic primitives
+- XRPL integration
+- Performance
+- UX
+- Production readiness
+
+Phase C1 is intentionally minimal and frozen.
+
+---
+
+## What Is XSTRP (In One Paragraph)
+
+XSTRP defines a transfer protocol in which funds cannot be irreversibly lost due to receiver
+inaction, malformed proofs, or adversarial interference. Transfers proceed through an explicit
+state machine and complete only upon valid receiver participation. All failure modes resolve
+to deterministic recovery.
+
+---
+
+## Frozen Scope (Phase C1)
+
+The following components are FINAL and immutable:
+
+- RFC-XSTRP-0001 (v1.0)
+- TransferIntent data model
+- State machine and transitions
+- CompletionProof v1 semantics
+- Proof validation enforcement
+- Optional IntentBinding metadata (non-enforced)
+- Serialization guarantees
+
+No cryptography or ledger integration exists in Phase C1.
+
+---
+
+## Threat Model Assumptions
+
+XSTRP assumes:
+- An adversarial environment
+- No trusted intermediaries
+- No trusted transport
+- No trusted counterparty
+- Correctness of the underlying ledger (out of scope)
+
+Threats and guarantees are defined in `THREAT-MODEL.md`.
+
+---
+
+## Reviewer Guidance
+
+Reviewers are encouraged to focus on:
+- Whether any state allows permanent fund loss
+- Whether invalid or malicious actions can force completion
+- Whether recovery paths are sound and unambiguous
+- Whether the protocol violates its own stated guarantees
+
+Suggested questions:
+- Can funds become stranded?
+- Can completion occur without receiver intent?
+- Can sender intent be altered post-creation?
+- Are failure modes exhaustive?
+
+---
+
+## Review Boundary
+
+This review applies strictly to Phase C1 as frozen at:
+
+**Release:** `v1.0.0-core`
+
+Any findings should reference this boundary explicitly.