Issue Lifecycle Actions (#4071)

## Description:

# Issue Lifecycle Actions

Adds two GitHub Actions workflows that enforce OpenFront's
issue-lifecycle invariants. No LLM calls — only the default
`GITHUB_TOKEN`. Layer B (Claude-powered triage) will build on this
foundation.

## Summary

- **Stale closer** — daily cron. Unmilestoned issues get warned at 5
days of inactivity, auto-closed at 10. Exempt: milestoned or
`keep-open`. Bot comments don't reset the timer.
- **Assignment invariant** — event + cron backstop. You cannot assign
anyone to an unmilestoned issue. Violators are unassigned automatically
with an explanatory comment.
- **Approval label sync** — event + cron backstop. The `not-approved`
(red) and `approved` (green) labels are derived from milestone state.
These labels are *only* ever touched by this Action.

## Rollout

Both workflows ship gated by `vars.ISSUE_LIFECYCLE_DRY_RUN` (defaults to
`'true'`). They log decisions but do not mutate anything until the
maintainer flips that variable in **Settings → Variables**.

Suggested rollout:
1. Merge with dry-run on.
2. Watch the cron logs for ~1 week. Verify the action list matches
expectations.
3. Flip `ISSUE_LIFECYCLE_DRY_RUN=false` to go live.

## File layout

```
.github/workflows/
  issue-lifecycle-cron.yml      # daily 06:00 UTC + workflow_dispatch
  issue-lifecycle-events.yml    # issues: [opened, assigned, milestoned, demilestoned]
scripts/issue-lifecycle/
  config.ts                     # labels, colors, thresholds, comment templates
  github.ts                     # Octokit wrapper, Action applier, label idempotent-creation
  rules/
    approval-label-sync.ts      # pure function — idempotent
    assignment-invariant.ts     # pure function
    stale-closer.ts             # async — reads comment history, filters bots
  cron.ts                       # daily sweep orchestrator
  events.ts                     # event-mode dispatcher
  index.ts                      # entrypoint, CLI arg parser
  README.md
```

Structure mirrors `scripts/pr-gate/` from Unit 2 — same Octokit/Action
patterns, same dry-run convention.

## Self-installing labels

On every run, the Action ensures the six labels exist (`not-approved`,
`approved`, `stale`, `keep-open`, `needs-info`, `auto-closed-stale`)
with the correct colors and descriptions. No manual setup required.

## Local testing

```bash
cd scripts/issue-lifecycle
npm install
export GITHUB_TOKEN=ghp_...

# Full cron sweep, dry-run (default for CLI):
npx tsx index.ts --mode cron

# Simulate an event:
EVENT_NAME=assigned npx tsx index.ts --mode event --issue 1234
```

CLI invocations are dry-run unless `--no-dry-run` is passed explicitly.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

scripts/issue-lifecycle/events.ts

@@ -0,0 +1,74 @@
+import type { Octokit } from "@octokit/rest";
+import { type Action, applyActions, describeAction, getIssue } from "./github";
+import { syncApprovalLabel } from "./rules/approval-label-sync";
+import { enforceAssignmentInvariant } from "./rules/assignment-invariant";
+
+export type EventName = "opened" | "assigned" | "milestoned" | "demilestoned";
+
+export function isKnownEvent(name: string): name is EventName {
+  return (
+    name === "opened" ||
+    name === "assigned" ||
+    name === "milestoned" ||
+    name === "demilestoned"
+  );
+}
+
+export async function runEvent(
+  octokit: Octokit,
+  eventName: string,
+  issueNumber: number,
+  dryRun: boolean,
+): Promise<void> {
+  if (!isKnownEvent(eventName)) {
+    console.log(
+      `[issue-lifecycle] issue #${issueNumber} — event "${eventName}" not handled by this Action`,
+    );
+    return;
+  }
+
+  const issue = await getIssue(octokit, issueNumber);
+  if (!issue) return;
+  if (issue.is_pull_request) {
+    console.log(`[issue-lifecycle] issue #${issueNumber} is a PR — skipping`);
+    return;
+  }
+
+  const prefix = `[issue-lifecycle] issue #${issueNumber} (event: ${eventName})`;
+  const buckets: { rule: string; actions: Action[] }[] = [];
+
+  if (eventName === "assigned" || eventName === "demilestoned") {
+    buckets.push({
+      rule: "assignment-invariant",
+      actions: enforceAssignmentInvariant(issue),
+    });
+  }
+
+  if (
+    eventName === "opened" ||
+    eventName === "milestoned" ||
+    eventName === "demilestoned"
+  ) {
+    buckets.push({
+      rule: "approval-label-sync",
+      actions: syncApprovalLabel(issue),
+    });
+  }
+
+  let acted = false;
+  for (const { rule, actions } of buckets) {
+    if (actions.length === 0) continue;
+    acted = true;
+    console.log(
+      `${prefix} — rule: ${rule} — actions: ${actions.map(describeAction).join(", ")}`,
+    );
+    if (dryRun) {
+      console.log(`${prefix} — DRY_RUN: not applied`);
+      continue;
+    }
+    await applyActions(octokit, issueNumber, actions);
+  }
+  if (!acted) {
+    console.log(`${prefix} — no actions needed`);
+  }
+}