fix(dashboard): address PR review comments on widget edit

1. Fix stale `fields` in mergeQueries — destructure to omit existing
   `fields` so prepareWidgetQueries recomputes from updated aggregates/
   columns (bugbot comment #1)

2. Preserve widgetType without silent default — only set widgetType if
   explicitly provided via --dataset or already on the existing widget,
   preventing parseWidgetInput from defaulting to "spans" (bugbot #4)

3. Resolve aliases in paren passthrough — `spm()` now correctly resolves
   to `epm()` instead of being rejected by validation (bugbot #3)

Comment #2 (drops interval/thresholds) is not a real issue — these fields
are already stripped by the allowlist in stripWidgetServerFields before
buildReplacement sees them.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: betegon

src/commands/dashboard/widget/edit.ts

@@ -63,9 +63,12 @@ function mergeQueries(
     return; // signal: keep existing
   }
 
+  // Destructure to omit stale `fields` — prepareWidgetQueries will
+  // recompute it from the updated aggregates/columns.
+  const { fields: _staleFields, ...base } = existingQuery ?? {};
   return [
     {
-      ...existingQuery,
+      ...base,
       ...(flags.query && { aggregates: flags.query.map(parseAggregate) }),
       ...(flags.where !== undefined && { conditions: flags.where }),
       ...(flags["group-by"] && { columns: flags["group-by"] }),
@@ -81,7 +84,6 @@ function buildReplacement(
 ): DashboardWidget {
   const mergedQueries = mergeQueries(flags, existing.queries?.[0]);
 
-  const widgetType = flags.dataset ?? existing.widgetType;
   const limit = flags.limit !== undefined ? flags.limit : existing.limit;
 
   const raw: Record<string, unknown> = {
@@ -90,8 +92,12 @@ function buildReplacement(
     queries: mergedQueries ?? existing.queries,
     layout: existing.layout,
   };
-  if (widgetType) {
-    raw.widgetType = widgetType;
+  // Only set widgetType if explicitly provided via --dataset or already on the widget.
+  // Avoids parseWidgetInput defaulting to "spans" for widgets without a widgetType.
+  if (flags.dataset) {
+    raw.widgetType = flags.dataset;
+  } else if (existing.widgetType) {
+    raw.widgetType = existing.widgetType;
   }
   if (limit !== undefined) {
     raw.limit = limit;

src/types/dashboard.ts

@@ -356,7 +356,11 @@ export const IsFilterValueSchema = z.enum(IS_FILTER_VALUES);
  */
 export function parseAggregate(input: string): string {
   if (input.includes("(")) {
-    return input;
+    // Resolve aliases even in paren form: spm() → epm(), tpm(x) → epm(x)
+    const parenIdx = input.indexOf("(");
+    const fn = input.slice(0, parenIdx);
+    const alias = AGGREGATE_ALIASES[fn];
+    return alias ? `${alias}${input.slice(parenIdx)}` : input;
   }
   const colonIdx = input.indexOf(":");
   if (colonIdx > 0) {