feat(webapp): show running version in Mini App footer

Compute `git describe --tags --always --dirty` at server startup
and expose via unauthenticated /api/version. Render as small muted
text at the bottom of the Mini App so the running version can be
confirmed at a glance.

Once tags exist, the badge will show e.g. v0.1.0 or v0.1.0-3-gSHA.
Until then it shows the short SHA.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server.py

@@ -9,6 +9,8 @@ import io
 import json
 import logging
 import os
+import pathlib
+import subprocess
 from urllib.parse import parse_qs
 
 from aiohttp import web
@@ -23,6 +25,24 @@ logging.basicConfig(
 logger = logging.getLogger(__name__)
 
 
+# ── Version (computed once at startup) ───────────────────────────
+
+def _compute_version() -> str:
+    """Return `git describe --tags --always --dirty`, or 'unknown'."""
+    try:
+        out = subprocess.run(
+            ["git", "describe", "--tags", "--always", "--dirty"],
+            cwd=pathlib.Path(__file__).parent,
+            capture_output=True, text=True, timeout=2, check=True,
+        )
+        return out.stdout.strip() or "unknown"
+    except (subprocess.SubprocessError, FileNotFoundError, OSError):
+        return "unknown"
+
+
+_VERSION = _compute_version()
+
+
 # ── Token (injected by start.py via env) ─────────────────────────
 
 def _get_bot_token() -> str:
@@ -206,6 +226,11 @@ async def api_export_json(request: web.Request):
     return web.json_response({"records": data, "count": len(data)})
 
 
+async def api_version(request: web.Request):
+    """Return the running server version. Unauthenticated."""
+    return web.json_response({"version": _VERSION})
+
+
 @require_auth
 async def api_export_csv(request: web.Request):
     """Export all workouts as CSV."""
@@ -239,9 +264,9 @@ def create_app() -> web.Application:
     app.router.add_get("/api/stats", api_get_stats)
     app.router.add_get("/api/export/json", api_export_json)
     app.router.add_get("/api/export/csv", api_export_csv)
+    app.router.add_get("/api/version", api_version)
 
     # Serve the webapp/ folder
-    import pathlib
     webapp_dir = pathlib.Path(__file__).parent / "webapp"
 
     async def index_handler(request):

webapp/app.js

@@ -767,8 +767,22 @@ function fmtWeight(w) {
   return w === Math.floor(w) ? Math.floor(w).toString() : w.toString();
 }
 
+// ── Version badge ───────────────────────────────────────────────
+async function loadVersion() {
+  try {
+    const res = await fetch(API + "/version");
+    if (!res.ok) return;
+    const data = await res.json();
+    const badge = document.getElementById("version-badge");
+    if (badge && data.version) badge.textContent = data.version;
+  } catch (e) {
+    // Silent — footer just stays empty if unreachable
+  }
+}
+
 // ── Init ────────────────────────────────────────────────────────
 async function init() {
+  loadVersion();
   if (!userId) return;
   try {
     const data = await api("GET", "/exercises");

webapp/index.html

@@ -88,6 +88,10 @@
         <p>Loading...</p>
       </div>
     </div>
+
+    <footer id="app-footer">
+      <span id="version-badge"></span>
+    </footer>
   </div>
 
   <script src="app.js"></script>

webapp/style.css

@@ -472,3 +472,15 @@ details[open] .raw-toggle::before {
   transform: translateX(-50%) translateY(0);
   opacity: 1;
 }
+
+/* ── Footer / version badge ──────────────────────────────────── */
+
+#app-footer {
+  margin-top: 24px;
+  padding: 12px 16px 20px;
+  text-align: center;
+  font-size: 11px;
+  color: var(--tg-theme-hint-color, #999);
+  opacity: 0.6;
+  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+}