improvement(copilot): stamp docs grep fan-out size on the grep span

A directory-scoped docs grep now records copilot.vfs.grep.docs_page_count
(pages fetched from the live site) on the active tool span, mirroring the
new contract attribute.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: j15z

apps/sim/lib/copilot/docs/docs-corpus.ts

@@ -1,9 +1,11 @@
+import { trace } from '@opentelemetry/api'
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import { sleep } from '@sim/utils/helpers'
 import { backoffWithJitter } from '@sim/utils/retry'
 import { foldDocsIndexPath } from '@/lib/copilot/docs/docs-path'
 import { DOCS_MANIFEST } from '@/lib/copilot/generated/docs-manifest'
+import { TraceAttr } from '@/lib/copilot/generated/trace-attributes-v1'
 import type { GrepCountEntry, GrepMatch, GrepOptions } from '@/lib/copilot/vfs/operations'
 import { glob as globPaths, grep, grepReadResult } from '@/lib/copilot/vfs/operations'
 import { mapWithConcurrency } from '@/lib/core/utils/concurrency'
@@ -212,6 +214,7 @@ export async function grepDocs(
   }
   const dir = `${key}/`
   const pages = [...docsKeyView.keys()].filter((pageKey) => pageKey.startsWith(dir))
+  trace.getActiveSpan()?.setAttribute(TraceAttr.CopilotVfsGrepDocsPageCount, pages.length)
   let unreachable = 0
   const results = await mapWithConcurrency(pages, GREP_FETCH_CONCURRENCY, async (pageKey) => {
     // Once any page is unreachable the grep is going to fail — skip the

apps/sim/lib/copilot/generated/trace-attributes-v1.ts

@@ -278,6 +278,7 @@ export const TraceAttr = {
   CopilotVfsFileMediaType: 'copilot.vfs.file.media_type',
   CopilotVfsFileName: 'copilot.vfs.file.name',
   CopilotVfsFileSizeBytes: 'copilot.vfs.file.size_bytes',
+  CopilotVfsGrepDocsPageCount: 'copilot.vfs.grep.docs_page_count',
   CopilotVfsHasAlpha: 'copilot.vfs.has_alpha',
   CopilotVfsInputBytes: 'copilot.vfs.input.bytes',
   CopilotVfsInputHeight: 'copilot.vfs.input.height',
@@ -922,6 +923,7 @@ export const TraceAttrValues: readonly TraceAttrValue[] = [
   'copilot.vfs.file.media_type',
   'copilot.vfs.file.name',
   'copilot.vfs.file.size_bytes',
+  'copilot.vfs.grep.docs_page_count',
   'copilot.vfs.has_alpha',
   'copilot.vfs.input.bytes',
   'copilot.vfs.input.height',