Fix arithmetic overflow in query_stats collector (#547)

DMV sys.dm_exec_query_stats returns min_dop, max_dop, and thread
columns as bigint, but our temp table and permanent table used
smallint/integer — causing overflow on INSERT.

Widened to match actual DMV types:
- min_dop, max_dop: smallint -> bigint
- min/max_reserved_threads, min/max_used_threads: integer -> bigint

Includes upgrade script for existing 2.2.0 installations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: erikdarlingdata

install/02_create_tables.sql

@@ -119,18 +119,18 @@ BEGIN
         max_rows bigint NOT NULL,
         statement_sql_handle varbinary(64) NULL,
         statement_context_id bigint NULL,
-        min_dop smallint NOT NULL,
-        max_dop smallint NOT NULL,
+        min_dop bigint NOT NULL,
+        max_dop bigint NOT NULL,
         min_grant_kb bigint NOT NULL,
         max_grant_kb bigint NOT NULL,
         min_used_grant_kb bigint NOT NULL,
         max_used_grant_kb bigint NOT NULL,
         min_ideal_grant_kb bigint NOT NULL,
         max_ideal_grant_kb bigint NOT NULL,
-        min_reserved_threads integer NOT NULL,
-        max_reserved_threads integer NOT NULL,
-        min_used_threads integer NOT NULL,
-        max_used_threads integer NOT NULL,
+        min_reserved_threads bigint NOT NULL,
+        max_reserved_threads bigint NOT NULL,
+        min_used_threads bigint NOT NULL,
+        max_used_threads bigint NOT NULL,
         total_spills bigint NOT NULL,
         min_spills bigint NOT NULL,
         max_spills bigint NOT NULL,

install/08_collect_query_stats.sql

@@ -202,18 +202,18 @@ BEGIN
             max_rows bigint NOT NULL,
             statement_sql_handle varbinary(64) NULL,
             statement_context_id bigint NULL,
-            min_dop smallint NOT NULL,
-            max_dop smallint NOT NULL,
+            min_dop bigint NOT NULL,
+            max_dop bigint NOT NULL,
             min_grant_kb bigint NOT NULL,
             max_grant_kb bigint NOT NULL,
             min_used_grant_kb bigint NOT NULL,
             max_used_grant_kb bigint NOT NULL,
             min_ideal_grant_kb bigint NOT NULL,
             max_ideal_grant_kb bigint NOT NULL,
-            min_reserved_threads integer NOT NULL,
-            max_reserved_threads integer NOT NULL,
-            min_used_threads integer NOT NULL,
-            max_used_threads integer NOT NULL,
+            min_reserved_threads bigint NOT NULL,
+            max_reserved_threads bigint NOT NULL,
+            min_used_threads bigint NOT NULL,
+            max_used_threads bigint NOT NULL,
             total_spills bigint NOT NULL,
             min_spills bigint NOT NULL,
             max_spills bigint NOT NULL,