Add query timing metadata to reporter output

.claude/skills/query-reporter/SKILL.md

@@ -50,10 +50,12 @@ Each query in the log file looks like:
 
 ```sql
 -- MusicLibrary.Collection.list_records/2, at: lib/music_library/collection.ex:42
+-- total=2.6ms db=2.6ms queue=0.0ms decode=0.0ms
 SELECT r0."id", r0."title" FROM "records" AS r0 WHERE (r0."purchased_at" IS NOT NULL) LIMIT 20;
 ```
 
-- The SQL comment shows the Elixir function and file:line that originated the query
+- The first comment shows the Elixir function and file:line that originated the query
+- The second comment shows timing: total, db (query execution), queue (connection wait), decode
 - Parameters are fully interpolated (no `?` placeholders)
 - Each query ends with `;` and is separated by a blank line
 - Queries are executable — you can paste them into `sqlite3` or `mcp__tidewave__execute_sql_query`

lib/music_library/query_reporter.ex

@@ -57,8 +57,8 @@ defmodule MusicLibrary.QueryReporter do
 
   # sobelow_skip ["Traversal.FileModule"]
   @doc false
-  def handle_event(@event, _measurements, metadata, file_path) do
-    entry = format_entry(metadata)
+  def handle_event(@event, measurements, metadata, file_path) do
+    entry = format_entry(metadata, measurements)
     # Path is provided by the developer at runtime via IEx/Tidewave
     File.write!(file_path, entry, [:append])
   rescue
@@ -66,18 +66,47 @@ defmodule MusicLibrary.QueryReporter do
       Logger.warning("QueryReporter failed to write: #{inspect(error)}")
   end
 
-  defp format_entry(metadata) do
+  defp format_entry(metadata, measurements) do
     params = metadata.cast_params || metadata.params || []
     query = interpolate_query(metadata.query, params)
     location = extract_source_location(metadata.stacktrace)
+    timing = format_timing(measurements)
 
     IO.iodata_to_binary([
       if(location, do: [location, "\n"], else: []),
+      timing,
+      "\n",
       String.trim_trailing(query),
       ";\n\n"
     ])
   end
 
+  defp format_timing(measurements) do
+    parts =
+      [:total_time, :query_time, :queue_time, :decode_time]
+      |> Enum.flat_map(fn key ->
+        case Map.get(measurements, key) do
+          nil -> []
+          value -> [{key, to_ms(value)}]
+        end
+      end)
+
+    label = fn
+      :total_time -> "total"
+      :query_time -> "db"
+      :queue_time -> "queue"
+      :decode_time -> "decode"
+    end
+
+    formatted = Enum.map_join(parts, " ", fn {key, ms} -> "#{label.(key)}=#{ms}ms" end)
+    "-- #{formatted}"
+  end
+
+  defp to_ms(native) do
+    us = System.convert_time_unit(native, :native, :microsecond)
+    Float.round(us / 1000, 1)
+  end
+
   defp interpolate_query(query, []), do: query
 
   defp interpolate_query(query, params) do