asdf

Squash the current repository state back into one baseline commit while
preserving the README reframing and repository contents.

Constraint: User explicitly requested a single squashed commit with subject "asdf"
Confidence: high
Scope-risk: broad
Reversibility: clean
Directive: This commit intentionally rewrites published history; coordinate before future force-pushes
Tested: git status clean; local history rewritten to one commit; force-pushed main to origin and instructkr
Not-tested: Fresh clone verification after push

src/utils/profilerBase.ts

@@ -0,0 +1,46 @@
+/**
+ * Shared infrastructure for profiler modules (startupProfiler, queryProfiler,
+ * headlessProfiler). All three use the same perf_hooks timeline and the same
+ * line format for detailed reports.
+ */
+
+import type { performance as PerformanceType } from 'perf_hooks'
+import { formatFileSize } from './format.js'
+
+// Lazy-load performance API only when profiling is enabled.
+// Shared across all profilers — perf_hooks.performance is a process-wide singleton.
+let performance: typeof PerformanceType | null = null
+
+export function getPerformance(): typeof PerformanceType {
+  if (!performance) {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    performance = require('perf_hooks').performance
+  }
+  return performance!
+}
+
+export function formatMs(ms: number): string {
+  return ms.toFixed(3)
+}
+
+/**
+ * Render a single timeline line in the shared profiler report format:
+ *   [+  total.ms] (+  delta.ms) name [extra] [| RSS: .., Heap: ..]
+ *
+ * totalPad/deltaPad control the padStart width so callers can align columns
+ * based on their expected magnitude (startup uses 8/7, query uses 10/9).
+ */
+export function formatTimelineLine(
+  totalMs: number,
+  deltaMs: number,
+  name: string,
+  memory: NodeJS.MemoryUsage | undefined,
+  totalPad: number,
+  deltaPad: number,
+  extra = '',
+): string {
+  const memInfo = memory
+    ? ` | RSS: ${formatFileSize(memory.rss)}, Heap: ${formatFileSize(memory.heapUsed)}`
+    : ''
+  return `[+${formatMs(totalMs).padStart(totalPad)}ms] (+${formatMs(deltaMs).padStart(deltaPad)}ms) ${name}${extra}${memInfo}`
+}