feat: lifecycle inference from the issue timeline (#5)

Fill the board's Steeping / In-review columns (and the calibration actuals)
from real gitea timeline events, replacing the three-column-only v0.

core (@commitea/core):
- inferLifecycle(issue, events, asOf): five-column inference — closed → done;
  open PR ref → review; commit ref → steeping; any triage signal → triage;
  else diagnosis. Earliest event of each kind fixes the stage timestamp.
- Derives actualWorkingDays (work-start → close) — the estimate-vs-actual the
  calibration fit (D3) learns from — and steepingDays (first commit → now) for
  the board age badge.
- workingDaysBetween(): whole Mon–Fri days in [start, end), day-granular.
- normalizeTimeline() + client.getIssueTimeline(): map gitea's raw timeline
  (label/milestone → triage, commit_ref → commit, pull_ref → pull, close,
  reopen), drop the rest. Paginated.

app:
- reconcile now fetches every issue's timeline and returns it keyed by number;
  threaded through the bridge → useBacklog → board/focus.
- issuesToBoardColumns + scheduleFocus run inferLifecycle: real Steeping/In-review
  columns, steeping-age `days` badge, focus-card steeping badge.

Known refinement: gitea's pull_ref fires on any PR mention, so an issue merely
referenced in a PR body can read as In-review; distinguishing closing refs from
mentions needs the PR link's state (later). Re-opening multi-segment actuals
also deferred.

Verified: 63 core tests green (15 lifecycle, incl. workingDaysBetween + the five
transitions), desktop typecheck clean, 14 fixture e2e green, live spec asserts
the board's Done column is populated from real events.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/core/src/lifecycle/lifecycle-v0.test.ts

@@ -1,6 +1,11 @@
 import { describe, expect, it } from 'vitest'
 
-import { inferColumnV0 } from './lifecycle-v0.js'
+import {
+  inferColumnV0,
+  inferLifecycle,
+  type LifecycleEvent,
+  workingDaysBetween,
+} from './lifecycle-v0.js'
 
 const base = { state: 'open' as const, labels: [] as string[], milestone: null }
 
@@ -27,3 +32,93 @@ describe('inferColumnV0', () => {
     expect(['steeping', 'review']).not.toContain(col)
   })
 })
+
+describe('workingDaysBetween', () => {
+  it('counts weekdays in [start, end), excluding weekends', () => {
+    // Mon 2026-01-05 → Mon 2026-01-12 spans a full week = 5 working days
+    expect(workingDaysBetween(new Date('2026-01-05'), new Date('2026-01-12'))).toBe(5)
+  })
+
+  it('is 0 for same day or reversed', () => {
+    expect(workingDaysBetween(new Date('2026-01-05'), new Date('2026-01-05'))).toBe(0)
+    expect(workingDaysBetween(new Date('2026-01-12'), new Date('2026-01-05'))).toBe(0)
+  })
+
+  it('skips a weekend inside the interval', () => {
+    // Fri 2026-01-09 → Mon 2026-01-12: only Fri counts (Sat/Sun excluded) = 1
+    expect(workingDaysBetween(new Date('2026-01-09'), new Date('2026-01-12'))).toBe(1)
+  })
+})
+
+describe('inferLifecycle', () => {
+  const openBase = { ...base, createdAt: '2026-01-05T09:00:00Z', closedAt: null }
+  const asOf = new Date('2026-01-14T09:00:00Z')
+
+  const ev = (type: LifecycleEvent['type'], at: string): LifecycleEvent => ({ type, at })
+
+  it('bare open issue with no events is diagnosis', () => {
+    const inf = inferLifecycle(openBase, [], asOf)
+    expect(inf.column).toBe('diagnosis')
+    expect(inf.stages.opened).toBe(openBase.createdAt)
+    expect(inf.actualWorkingDays).toBeNull()
+    expect(inf.steepingDays).toBeNull()
+  })
+
+  it('a triage event (or a current label) moves it to triage', () => {
+    expect(inferLifecycle(openBase, [ev('triage', '2026-01-06T09:00:00Z')], asOf).column).toBe('triage')
+    expect(inferLifecycle({ ...openBase, labels: ['p/1'] }, [], asOf).column).toBe('triage')
+  })
+
+  it('a commit ref moves an open issue to steeping and counts its working age', () => {
+    const inf = inferLifecycle(
+      { ...openBase, labels: ['est/2d'] },
+      [ev('triage', '2026-01-05T10:00:00Z'), ev('commit', '2026-01-07T12:00:00Z')],
+      asOf,
+    )
+    expect(inf.column).toBe('steeping')
+    expect(inf.stages.steeping).toBe('2026-01-07T12:00:00Z')
+    // Wed 2026-01-07 → Wed 2026-01-14 = 5 working days
+    expect(inf.steepingDays).toBe(5)
+  })
+
+  it('a pull ref outranks a commit ref → review', () => {
+    const inf = inferLifecycle(
+      openBase,
+      [ev('commit', '2026-01-07T12:00:00Z'), ev('pull', '2026-01-08T12:00:00Z')],
+      asOf,
+    )
+    expect(inf.column).toBe('review')
+    expect(inf.steepingDays).toBeNull() // only steeping issues carry an age
+  })
+
+  it('closed → done, with actual working time from work-start to close', () => {
+    const inf = inferLifecycle(
+      { ...openBase, state: 'closed', closedAt: '2026-01-12T09:00:00Z' },
+      [ev('commit', '2026-01-07T09:00:00Z'), ev('pull', '2026-01-08T09:00:00Z'), ev('close', '2026-01-12T09:00:00Z')],
+      asOf,
+    )
+    expect(inf.column).toBe('done')
+    expect(inf.stages.done).toBe('2026-01-12T09:00:00Z')
+    // Wed 2026-01-07 → Mon 2026-01-12 = Wed,Thu,Fri = 3 working days
+    expect(inf.actualWorkingDays).toBe(3)
+  })
+
+  it('takes the earliest event of each kind for stage timestamps', () => {
+    const inf = inferLifecycle(
+      openBase,
+      [ev('commit', '2026-01-09T09:00:00Z'), ev('commit', '2026-01-07T09:00:00Z')],
+      asOf,
+    )
+    expect(inf.stages.steeping).toBe('2026-01-07T09:00:00Z')
+  })
+
+  it('falls back to opened when a closed issue has no work-start signal', () => {
+    const inf = inferLifecycle(
+      { ...openBase, state: 'closed', closedAt: '2026-01-08T09:00:00Z' },
+      [ev('close', '2026-01-08T09:00:00Z')],
+      asOf,
+    )
+    // Mon 2026-01-05 → Thu 2026-01-08 = Mon,Tue,Wed = 3 working days
+    expect(inf.actualWorkingDays).toBe(3)
+  })
+})