feat: jobs system with dedicated nav page and run history

Replaces ad-hoc Tailscale config tracking with a proper jobs system.
Jobs get their own nav page (master/detail layout), a dedicated DB
table, and full run history persisted forever. Tailscale connection
settings move from the Settings modal into the Jobs page. Registry
pattern makes adding future jobs straightforward.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/db.test.js

@@ -4,6 +4,7 @@ import {
   getInstances, getInstance, getDistinctStacks,
   createInstance, updateInstance, deleteInstance, importInstances, getInstanceHistory,
   getConfig, setConfig,
+  getJobs, getJob, createJob, updateJob, createJobRun, completeJobRun, getJobRuns,
 } from '../server/db.js'
 
 beforeEach(() => _resetForTest());
@@ -299,3 +300,89 @@ describe('getConfig / setConfig', () => {
     expect(getConfig('tailscale_api_key')).toBe('');
   });
 });
+
+// ── jobs ──────────────────────────────────────────────────────────────────────
+
+const baseJob = {
+  key: 'test_job', name: 'Test Job', description: 'desc',
+  enabled: 0, schedule: 15, config: '{}',
+};
+
+describe('jobs', () => {
+  it('returns empty array when no jobs', () => {
+    expect(getJobs()).toEqual([]);
+  });
+
+  it('createJob + getJobs returns the job', () => {
+    createJob(baseJob);
+    expect(getJobs()).toHaveLength(1);
+    expect(getJobs()[0].name).toBe('Test Job');
+  });
+
+  it('getJob returns null for unknown id', () => {
+    expect(getJob(999)).toBeNull();
+  });
+
+  it('updateJob changes enabled and schedule', () => {
+    createJob(baseJob);
+    const id = getJobs()[0].id;
+    updateJob(id, { enabled: 1, schedule: 30, config: '{}' });
+    expect(getJob(id).enabled).toBe(1);
+    expect(getJob(id).schedule).toBe(30);
+  });
+
+  it('getJobs includes last_status null when no runs', () => {
+    createJob(baseJob);
+    expect(getJobs()[0].last_status).toBeNull();
+  });
+
+  it('getJobs reflects last_status after a run', () => {
+    createJob(baseJob);
+    const id = getJobs()[0].id;
+    const runId = createJobRun(id);
+    completeJobRun(runId, 'success', 'ok');
+    expect(getJobs()[0].last_status).toBe('success');
+  });
+});
+
+// ── job_runs ──────────────────────────────────────────────────────────────────
+
+describe('job_runs', () => {
+  it('createJobRun returns a positive id', () => {
+    createJob(baseJob);
+    const id = getJobs()[0].id;
+    expect(createJobRun(id)).toBeGreaterThan(0);
+  });
+
+  it('new run has status running and no ended_at', () => {
+    createJob(baseJob);
+    const id = getJobs()[0].id;
+    const runId = createJobRun(id);
+    const runs = getJobRuns(id);
+    expect(runs[0].status).toBe('running');
+    expect(runs[0].ended_at).toBeNull();
+  });
+
+  it('completeJobRun sets status, result, and ended_at', () => {
+    createJob(baseJob);
+    const id = getJobs()[0].id;
+    const runId = createJobRun(id);
+    completeJobRun(runId, 'success', '2 updated of 8');
+    const run = getJobRuns(id)[0];
+    expect(run.status).toBe('success');
+    expect(run.result).toBe('2 updated of 8');
+    expect(run.ended_at).not.toBeNull();
+  });
+
+  it('getJobRuns returns newest first', () => {
+    createJob(baseJob);
+    const id = getJobs()[0].id;
+    const r1 = createJobRun(id);
+    const r2 = createJobRun(id);
+    completeJobRun(r1, 'success', 'first');
+    completeJobRun(r2, 'error', 'second');
+    const runs = getJobRuns(id);
+    expect(runs[0].id).toBe(r2);
+    expect(runs[1].id).toBe(r1);
+  });
+});