A run says whether the dashboard, the CLI or a script asked for it

`POST /runs/flows/{name}` hardcoded `cause: "api"`, so every row in the
history claimed the same origin. The body now carries an optional `cause`,
closed to the values the column knows — the dashboard sends nothing and stays
"api", `fluksio run` says "cli", and the SDK client says "sdk".

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013Gf7WaExcJ9bs3kfJXB3nK

backend/fluksio/sdk/client.py

@@ -226,11 +226,19 @@ class Client:
         params: dict[str, Any] | None = None,
         seed: int | None = None,
         no_cache: bool = False,
+        cause: str = "sdk",
     ) -> RunHandle:
+        """Queue a run. ``cause`` is what the history records it as coming
+        from — a script is the default, `fluksio run` says so itself."""
         row = self._call(
             "POST",
             f"/runs/flows/{flow}",
-            json={"params": params or {}, "seed": seed, "no_cache": no_cache},
+            json={
+                "params": params or {},
+                "seed": seed,
+                "no_cache": no_cache,
+                "cause": cause,
+            },
         )
         return RunHandle(self, row["id"], row)