Remove template-only ABI files that falsely implied formal verification

Template Idris2 ABI files (Types.idr, Layout.idr, Foreign.idr) contained
only RSR template scaffolding with unresolved placeholders and no
domain-specific proofs. Removed to prevent false impression of formal
verification coverage.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

PROOF-NEEDS.md

@@ -0,0 +1,10 @@
+# PROOF-NEEDS.md
+
+## Template ABI Cleanup (2026-03-29)
+
+Template ABI removed -- was creating false impression of formal verification.
+The removed files (Types.idr, Layout.idr, Foreign.idr) contained only RSR template
+scaffolding with unresolved {{PROJECT}}/{{AUTHOR}} placeholders and no domain-specific proofs.
+
+When this project needs formal ABI verification, create domain-specific Idris2 proofs
+following the pattern in repos like `typed-wasm`, `proven`, `echidna`, or `boj-server`.