feat(boulder-state): add formatDurationHuman utility

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/boulder-state/format-duration.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from "bun:test"
+import { formatDurationHuman } from "./format-duration"
+
+describe("formatDurationHuman", () => {
+  it("returns 0s for 0ms", () => {
+    expect(formatDurationHuman(0)).toBe("0s")
+  })
+
+  it("returns 0s for 999ms", () => {
+    expect(formatDurationHuman(999)).toBe("0s")
+  })
+
+  it("returns 1s for 1000ms", () => {
+    expect(formatDurationHuman(1000)).toBe("1s")
+  })
+
+  it("returns 1m 0s for 60_000ms", () => {
+    expect(formatDurationHuman(60_000)).toBe("1m 0s")
+  })
+
+  it("returns 1h 0m 0s for 3_600_000ms", () => {
+    expect(formatDurationHuman(3_600_000)).toBe("1h 0m 0s")
+  })
+
+  it("returns 1h 2m 3s for 3_723_456ms", () => {
+    expect(formatDurationHuman(3_723_456)).toBe("1h 2m 3s")
+  })
+
+  it("returns 24h 0m 0s for 86_400_000ms", () => {
+    expect(formatDurationHuman(86_400_000)).toBe("24h 0m 0s")
+  })
+})

src/features/boulder-state/format-duration.ts

@@ -0,0 +1,16 @@
+export function formatDurationHuman(milliseconds: number): string {
+  const totalSeconds = Math.max(0, Math.floor(milliseconds / 1000))
+  const hours = Math.floor(totalSeconds / 3600)
+  const minutes = Math.floor((totalSeconds % 3600) / 60)
+  const seconds = totalSeconds % 60
+
+  if (hours > 0) {
+    return `${hours}h ${minutes}m ${seconds}s`
+  }
+
+  if (minutes > 0) {
+    return `${minutes}m ${seconds}s`
+  }
+
+  return `${seconds}s`
+}

src/features/boulder-state/index.ts

@@ -2,3 +2,4 @@ export * from "./types"
 export * from "./constants"
 export * from "./storage"
 export * from "./top-level-task"
+export * from "./format-duration"