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/gitea/client.ts

@@ -6,6 +6,7 @@
  * get the full set.
  */
 
+import { type LifecycleEvent, type LifecycleEventType } from '../lifecycle/lifecycle-v0.js'
 import { extractLabelFacts } from '../labels/label-schema.js'
 import {
   GiteaApiError,
@@ -54,6 +55,33 @@ interface RawMilestoneFull {
   closed_issues: number
 }
 
+/** The subset of a gitea timeline comment we read. */
+interface RawTimelineComment {
+  type: string
+  created_at: string
+}
+
+/** gitea timeline `type` → our lifecycle signal. Unmapped types are dropped. */
+const TIMELINE_TYPE_MAP: Record<string, LifecycleEventType> = {
+  label: 'triage',
+  milestone: 'triage',
+  assignees: 'triage',
+  commit_ref: 'commit',
+  pull_ref: 'pull',
+  close: 'close',
+  reopen: 'reopen',
+}
+
+/** Map a raw gitea timeline to normalized lifecycle events. Pure. */
+export function normalizeTimeline(raw: RawTimelineComment[]): LifecycleEvent[] {
+  const out: LifecycleEvent[] = []
+  for (const c of raw) {
+    const type = TIMELINE_TYPE_MAP[c.type]
+    if (type && c.created_at) out.push({ type, at: c.created_at })
+  }
+  return out
+}
+
 export interface ListIssuesOptions {
   /** @default 'all' */
   state?: 'open' | 'closed' | 'all'
@@ -68,6 +96,8 @@ export interface GiteaClient {
   listMilestones(): Promise<GiteaMilestone[]>
   /** The issue indices this issue depends on (its blockers). */
   getIssueDependencies(index: number): Promise<number[]>
+  /** Normalized lifecycle events for one issue (all pages of its timeline). */
+  getIssueTimeline(index: number): Promise<LifecycleEvent[]>
 }
 
 /** Map raw gitea issue JSON to the normalized domain shape. Pure. */
@@ -163,5 +193,12 @@ export function createGiteaClient(config: GiteaConfig, fetchImpl: FetchLike): Gi
       const raw = (await request(`/issues/${index}/dependencies`)) as { number: number }[]
       return raw.map((d) => d.number)
     },
+
+    async getIssueTimeline(index) {
+      const raw = await requestAll<RawTimelineComment>(
+        (page) => `/issues/${index}/timeline?page=${page}&limit=${PAGE_LIMIT}`,
+      )
+      return normalizeTimeline(raw)
+    },
   }
 }