docs(site): address Copilot review on conformance page

- conformance.mdx "Run it yourself": wrap each per-suite command in a
  subshell so `cd sdk/go` no longer leaks into the next line; the snippet
  is now runnable top-to-bottom from the repo root.
- cross-sdk-tests/README: the surrounding commands run from cross-sdk-tests/,
  so point the count.py invocation at ../scripts/... and note the script
  resolves the repo root itself.
- count.py: read vector JSON with explicit encoding="utf-8" for reproducible,
  locale-independent counts, and catch UnicodeDecodeError in main() so a
  non-UTF-8 file exits 1 (documented) instead of tracing back.

Counts unchanged (total 69).

Author: claude

cross-sdk-tests/README.md

@@ -31,11 +31,11 @@ All vector files use the same Ed25519 keypair so any SDK can verify receipts sig
 
 ## Vector counts
 
-The per-set vector counts published on the Conformance page are generated from these files by [`scripts/conformance_matrix/count.py`](../scripts/conformance_matrix/count.py), so the numbers stay reproducible:
+The per-set vector counts published on the Conformance page are generated from these files by [`scripts/conformance_matrix/count.py`](../scripts/conformance_matrix/count.py), so the numbers stay reproducible. Run from this directory (the script resolves the repository root itself, so the output is the same from anywhere):
 
 ```sh
-python3 scripts/conformance_matrix/count.py             # human-readable table
-python3 scripts/conformance_matrix/count.py --format md  # Markdown for the page
+python3 ../scripts/conformance_matrix/count.py             # human-readable table
+python3 ../scripts/conformance_matrix/count.py --format md  # Markdown for the page
 ```
 
 ## Running

scripts/conformance_matrix/count.py

@@ -88,7 +88,7 @@ class VectorSet:
     counter: Callable[[dict[str, Any]], int]
 
     def count(self) -> int:
-        doc = json.loads((_REPO_ROOT / self.path).read_text())
+        doc = json.loads((_REPO_ROOT / self.path).read_text(encoding="utf-8"))
         return self.counter(doc)
 
 
@@ -239,7 +239,7 @@ def main(argv: list[str] | None = None) -> int:
 
     try:
         rows = collect()
-    except (OSError, json.JSONDecodeError, KeyError) as err:
+    except (OSError, UnicodeDecodeError, json.JSONDecodeError, KeyError) as err:
         print(f"error: could not count vectors: {err}", file=sys.stderr)
         return 1
 

site/src/content/docs/conformance.mdx

@@ -53,20 +53,20 @@ Path filtering scopes each run to the changed surface: a change to the shared ve
 
 ## Run it yourself
 
-The frozen vectors and the suites that consume them live in the repository. From a clone:
+The frozen vectors and the suites that consume them live in the repository. Run each line from the repository root; the per-suite commands use a subshell so the directory change does not leak into the next line:
 
 ```sh
 # Go: verify TS- and Python-signed receipts, reject the malformed corpus
-cd sdk/go && go test -tags=integration -v -run CrossLanguage
+(cd sdk/go && go test -tags=integration -v -run CrossLanguage)
 
 # Python: verify Go- and TS-signed receipts
-cd sdk/py && uv run pytest tests/test_cross_language_go.py tests/test_cross_language_ts.py -v
+(cd sdk/py && uv run pytest tests/test_cross_language_go.py tests/test_cross_language_ts.py -v)
 
 # TypeScript: verify Go- and Python-signed receipts
-cd sdk/ts && pnpm test -- cross-language
+(cd sdk/ts && pnpm test -- cross-language)
 
 # Shared spec-example and version-pinned vector checks
-cd cross-sdk-tests && go test -tags=integration -v
+(cd cross-sdk-tests && go test -tags=integration -v)
 
 # Regenerate the vector counts in the matrix above
 python3 scripts/conformance_matrix/count.py --format md