v2.8: 70-day cap, version badge, dates on the time axis

- max window is now 70 days (7d/30d/70d); retention lowered 300 -> 70 to match, so
  no data is kept that cannot be viewed
- /api/version endpoint; the share panel header shows the running version
- x-axis labels carry the date when the window spans more than a day: HH:MM under 6h,
  MM-DD + HH:MM between 6h and 24h, MM-DD beyond that; hover shows full date and time
- no sampling introduced, per your call: every stored sample is still returned as-is

Verified: /api/version ok, over-limit minutes falls back to 6h, axis formatter returns
09:29 for a 6h window and 07-23 for 70d.

Author: githubflyideas

config.go

@@ -28,7 +28,7 @@ func defaultConfig() *Config {
 		DataDir:       "./data",
 		TargetsDir:    "./targets",
 		Probe:         ProbeCfg{IntervalSec: 60, Packets: 20, GapMs: 50, TimeoutMs: 1000},
-		RetentionDays: 300,
+		RetentionDays: 70,
 	}
 }
 

static/index.html

@@ -113,8 +113,7 @@
       <button data-m="1440">24h</button>
       <button data-m="10080">7d</button>
       <button data-m="43200">30d</button>
-      <button data-m="129600">90d</button>
-      <button data-m="259200">180d</button>
+      <button data-m="100800">70d</button>
     </div>
     <div class="rng custom">
       <input type="datetime-local" id="customFrom" step="60">
@@ -136,7 +135,7 @@
     <div class="promo-b">This slot is for one VPS / IDC / network sponsor. Your GIF here — reach out on GitHub.</div>
   </a>
   <div class="promo share">
-    <div class="promo-h">LIKE PINGPING?</div>
+    <div class="promo-h">LIKE PINGPING? <span id="ver" style="color:var(--phos)"></span></div>
     <div class="promo-b">
       <a href="https://github.com/githubflyideas/pingping" target="_blank" rel="noopener">★ Star on GitHub</a>
       <span class="share-links" id="shareLinks"></span>
@@ -257,7 +256,17 @@
     animation: false,
     grid: { left: 52, right: 46, top: 18, bottom: 42 },
     xAxis: { type: 'time', axisLine: { lineStyle: { color: cssv('--grid-axis') } },
-             axisLabel: { color: cssv('--dim'), fontSize: 10 }, splitLine: { lineStyle: { color: cssv('--grid-split') } },
+             axisLabel: { color: cssv('--dim'), fontSize: 10,
+               formatter: v => {
+                 const d = new Date(v);
+                 const p = n => String(n).padStart(2, '0');
+                 // 长窗口显示日期,短窗口显示时刻;跨天时两行都给
+                 const span = sel ? (sel.to - sel.from) : minutes * 60;
+                 if (span > 86400) return `${p(d.getMonth()+1)}-${p(d.getDate())}`;
+                 if (span > 21600) return `${p(d.getMonth()+1)}-${p(d.getDate())}\n${p(d.getHours())}:${p(d.getMinutes())}`;
+                 return `${p(d.getHours())}:${p(d.getMinutes())}`;
+               } },
+             splitLine: { lineStyle: { color: cssv('--grid-split') } },
              axisPointer: { show: true, snap: false,
                lineStyle: { color: cssv('--dim'), opacity: .45 },
                label: { show: true, backgroundColor: cssv('--panel'), color: cssv('--ink'),
@@ -275,7 +284,7 @@
         const ts = params[0] && params[0].axisValue;
         const i = roundInfo[ts];
         if (!i) return '';
-        let html = `<b>${new Date(+ts).toLocaleTimeString()}</b>`;
+        let html = `<b>${new Date(+ts).toLocaleString()}</b>`;
         html += `<br>rtt min/avg/max/mdev = ${i.lo.toFixed(3)}/${i.avg.toFixed(3)}/${i.hi.toFixed(3)}/${i.mdev.toFixed(3)} ms`;
         html += `<br>median <b>${i.med.toFixed(1)} ms</b> · ${i.n} samples`;
         html += `<br><span style="color:${i.lp > 0 ? cssv('--alert') : cssv('--dim')}">loss <b>${i.lp.toFixed(0)}%</b> (${i.lost}/${i.s})</span>`;
@@ -333,6 +342,11 @@
 });
 
 // 分享的是公开项目主页,不是本地私有面板
+fetch('/api/version').then(r => r.json()).then(d => {
+  const el = document.getElementById('ver');
+  if (el && d.version) el.textContent = 'v' + d.version.replace(/^v/, '');
+}).catch(() => {});
+
 (function buildShare() {
   const url = 'https://github.com/githubflyideas/pingping';
   const text = 'pingping — a single-binary link quality oscilloscope. One binary. One graph. Zero guesswork.';

web.go

@@ -115,6 +115,10 @@ func serveWeb(cfg *Config, store *Store, users map[string]string) error {
 		writeJSON(w, map[string]bool{"ok": true})
 	})
 
+	mux.HandleFunc("/api/version", func(w http.ResponseWriter, r *http.Request) {
+		writeJSON(w, map[string]string{"version": version})
+	})
+
 	mux.HandleFunc("/api/targets", guard(func(w http.ResponseWriter, r *http.Request) {
 		now := time.Now()
 		type item struct {
@@ -160,7 +164,7 @@ func serveWeb(cfg *Config, store *Store, users map[string]string) error {
 		to, _ := strconv.ParseInt(q.Get("to"), 10, 64)
 		if from == 0 || to == 0 {
 			minutes, _ := strconv.Atoi(q.Get("minutes"))
-			if minutes <= 0 || minutes > 259200 { // up to 180 days
+			if minutes <= 0 || minutes > 100800 { // up to 70 days
 				minutes = 360
 			}
 			to = time.Now().Unix()