feat: read the real gitea backlog into the app (P1 thin slice)

The app now displays its own live backlog instead of fixtures. First
end of the sync loop — the tap-root (#1) grows list reads and a read
path through the Electron main process.

- @commitea/core: client gains `listIssues` (paginated, PRs excluded)
  and `listMilestones`; a `lifecycle-v0` mapper (closed→done,
  labelled/milestoned→triage, bare→diagnosis — steeping/review await
  event inference in P1-5). +10 unit tests.
- main: gitea bridge over IPC (token stays in main, never the renderer);
  config from env / .env.local; gated off under COMMITEA_E2E so the
  committed e2e stays on fixtures. Preload exposes the typed bridge.
- renderer: useBacklog() reconciles once on mount; issuesToBoardColumns
  shapes real issues into The pot. Board takes optional real columns +
  a loading state, falling back to demo fixtures when unconfigured.

Verified: 14 e2e green (fixture mode) + a gated live spec that launches
against the real repo — the board renders the actual 25 open + 9 closed
issues (screenshot). SQLite mirror + reconcile-on-a-timer + lifecycle
event inference are the next slices (#2/#3/#5).

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

packages/core/src/index.ts

@@ -9,14 +9,18 @@ export {
 } from './labels/label-schema.js'
 export type { EstimateLabel, LabelFacts, PriorityLabel } from './labels/label-schema.js'
 
-export { createGiteaClient, normalizeIssue } from './gitea/client.js'
-export type { GiteaClient } from './gitea/client.js'
+export { createGiteaClient, normalizeIssue, normalizeMilestone } from './gitea/client.js'
+export type { GiteaClient, ListIssuesOptions } from './gitea/client.js'
 export { GiteaApiError } from './gitea/types.js'
 export type {
   FetchLike,
   GiteaConfig,
   GiteaHttpResponse,
   GiteaIssue,
+  GiteaMilestone,
   GiteaMilestoneRef,
   GiteaRequestInit,
 } from './gitea/types.js'
+
+export { inferColumnV0, LIFECYCLE_COLUMNS } from './lifecycle/lifecycle-v0.js'
+export type { LifecycleColumn } from './lifecycle/lifecycle-v0.js'