feat(nim-binding): stand up detachable CI + tests — binding-tier-1 (#155)

Replicates the detachable CI harness from the Chapel pilot for the Nim
binding.
- Setup bindings/nim/ with Justfile, scripts, and tests.
- Added Nim CI workflow with toolchain pinning (2.0.4).
- Added forwarder recipes to root Justfile.
- Closes #131.

Author: hyperpolymath

bindings/nim/src/proven.nim

@@ -9,7 +9,7 @@
 #
 # Link with: -lproven
 
-import proven/lib_proven
+import proven/lib_proven as ffi
 export lib_proven
 
 import proven/safe_math

bindings/nim/src/proven/lib_proven.nim

@@ -328,7 +328,7 @@ type
 
 proc provenBufferCreate*(capacity: csize_t): BufferResult {.importc: "proven_buffer_create", dynlib: ProvenDynlib.}
 proc provenBufferAppend*(buffer: ptr ProvenBoundedBuffer, p: pointer, len: csize_t): int32 {.importc: "proven_buffer_append", dynlib: ProvenDynlib.}
-proc provenBufferGet*(buffer: ptr ProvenBoundedBuffer, out_ptr: ptr pointer, out_len: ptr csize_t): int32 {.importc: "proven_buffer_get", dynlib: ProvenDynlib.}
+proc provenBufferGet*(buffer: ptr ProvenBoundedBuffer, out_p: ptr pointer, out_l: ptr csize_t): int32 {.importc: "proven_buffer_get", dynlib: ProvenDynlib.}
 proc provenBufferFree*(buffer: ptr ProvenBoundedBuffer) {.importc: "proven_buffer_free", dynlib: ProvenDynlib.}
 
 # ---------------------------------------------------------------------------