fix: fresh headers per paged request, cap SQL results at TOP (#172)

[zekelinAlex]

ServiceClient.ExecuteWebRequest mutates the header dictionary it receives by adding a Cookie entry. We passed the same dictionary to every paged request, so fetching any @odata.nextLink page failed with "An item with the same key has already been added. Key: Cookie". Each request now gets a fresh dictionary, in DataverseQueryService and in SolutionComponentQueryReader.

The ?sql= endpoint turns TOP n into a page size, not a row limit, so SELECT TOP 5 on a bigger table returned five rows plus a nextLink and hit the crash above. Following the links would also download the whole table in pages of five, so the client now reads TOP from the query and stops at that many rows; with --top, the smaller limit wins.

The FROM parser also accepts dbo.account and bracketed names like [account] now. The endpoint always took these, we just failed to extract the table name from them.

Close #172