formatDuration emits invalid strings at rounding boundaries ("60.0s", "1m 60s", "59m 60s") #521

Description

formatDuration (lib/format-duration.ts:17) rounds the seconds component after it has
already committed to a minute/hour bucket, so when the rounded value lands on 60 it is never
carried up. This produces strings that are never supposed to exist.

This function is reused for tool-call durations across lib/codex-sessions.ts,
lib/cursor-sessions.ts, lib/goose-sessions.ts, and session duration in lib/log-stats.ts,
so these malformed strings surface on real transcripts in the dashboard/CLI.

Steps to Reproduce

import { formatDuration } from "./lib/format-duration";

formatDuration(59999);   // => "60.0s"   (expected "1m 0s")
formatDuration(119600);  // => "1m 60s"  (expected "2m 0s")
formatDuration(3599600); // => "59m 60s" (expected "1h 0m")

Expected Behavior

Durations should always be normalised: 60.0s → 1m 0s, 1m 60s → 2m 0s, 59m 60s → 1h 0m.

Failproof AI Version

0.0.14-beta.1

Node.js / Bun Version

Bun 1.3+

Operating System

macOS

Additional Context

Durations should always be normalised: 60.0s → 1m 0s, 1m 60s → 2m 0s, 59m 60s → 1h 0m.