sync(cartridges/007-mcp): BindAddress.proof → .witness (closes #32) (#33)

Cartridge sync from \`boj-server-cartridges#34\` (merged 2026-06-02
13:12Z).

\`proof\` is a reserved keyword in Idris2 0.8.0; cannot be a record
field. Two-line rename: field declaration + one call site.

## Refs

- boj-server-cartridges#34 (canonical)
- valence-shell#112 (precedent + symptom report)
- Memory: reference_idris2_0_8_0_reserved_keywords.md

Closes #32.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

cartridges/007-mcp/abi/Oo7Mcp/SafeCli.idr

@@ -46,7 +46,7 @@ record BindAddress where
   constructor MkBindAddress
   host     : String
   port     : Int
-  proof    : IsLoopback
+  witness  : IsLoopback
 
 ||| The one and only production bind — 127.0.0.1:1066.
 ||| Port 1066 chosen in design-log decision-log 2026-04-20.
@@ -68,7 +68,7 @@ oo7_mcp_bind_port = cartridgeBind.port
 ||| Lets the adapter sanity-check that the proof travelled across FFI.
 export
 oo7_mcp_bind_family : Int
-oo7_mcp_bind_family = case cartridgeBind.proof of
+oo7_mcp_bind_family = case cartridgeBind.witness of
   Ipv4Loopback => 4
   Ipv6Loopback => 6