Add GET /api/stats/summary -> .gravity.last_update

[DL6ER]

What does this implement/fix?

Add GET /api/stats/summary -> .gravity.last_update timestamp exposing the last gravity update via the API.

This re-adds a functionality that was implemented in PHP and - apparently - forgotten when porting all the functions over into the new v6 API.

Example

d@r:~$ pihole api stats/summary

Requesting: GET http://localhost:80/api/stats/summary

Status: 200
Data:
{
  "queries": {
    "total": 83371,
    "blocked": 2079,
    "percent_blocked": 2.4936728477478027,
    "unique_domains": 2077,
    "forwarded": 61486,
    "cached": 19594,
    "types": {
      "A": 44317,
      "AAAA": 6610,
      "ANY": 0,
      "SRV": 15,
      "SOA": 0,
      "PTR": 452,
      "TXT": 12,
      "NAPTR": 0,
      "MX": 0,
      "DS": 1010,
      "RRSIG": 0,
      "DNSKEY": 29391,
      "NS": 0,
      "SVCB": 47,
      "HTTPS": 1517,
      "OTHER": 0
    },
    "status": {
      "UNKNOWN": 0,
      "GRAVITY": 1975,
      "FORWARDED": 61484,
      "CACHE": 10054,
      "REGEX": 0,
      "DENYLIST": 0,
      "EXTERNAL_BLOCKED_IP": 0,
      "EXTERNAL_BLOCKED_NULL": 0,
      "EXTERNAL_BLOCKED_NXRA": 0,
      "GRAVITY_CNAME": 74,
      "REGEX_CNAME": 0,
      "DENYLIST_CNAME": 0,
      "RETRIED": 2,
      "RETRIED_DNSSEC": 0,
      "IN_PROGRESS": 212,
      "DBBUSY": 0,
      "SPECIAL_DOMAIN": 30,
      "CACHE_STALE": 9540
    },
    "replies": {
      "UNKNOWN": 89,
      "NODATA": 32998,
      "NXDOMAIN": 396,
      "CNAME": 6033,
      "IP": 13724,
      "DOMAIN": 394,
      "RRNAME": 10,
      "SERVFAIL": 5,
      "REFUSED": 0,
      "NOTIMP": 0,
      "OTHER": 0,
      "DNSSEC": 725,
      "NONE": 28911,
      "BLOB": 86
    }
  },
  "clients": {
    "active": 20,
    "total": 20
  },
  "gravity": {
    "domains_being_blocked": 236457,
    "last_update": 1725153123                   <-------------------------------
  },
  "took": 0.000253915786743164
}

---

Related issue or feature (if applicable): https://discourse.pi-hole.net/t/domains-on-adlists-doesnt-show-last-gravity-update/72082

Pull request in docs with documentation (if applicable): N/A

---

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Checklist:

• The code change is tested and works locally.
• I based my code and PRs against the repositories developmental branch.
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[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/domains-on-adlists-doesnt-show-last-gravity-update/72082/8