UI redesign v2: modern ant/mono design + app version (v2.0.0)

app.py

@@ -48,6 +48,9 @@ for _d in (UPLOAD_DIR, OUTPUT_DIR, WORK_DIR):
 
 MAX_UPLOAD_MB = 400
 
+# Semantic version exposed by /health so the UI can show "vX.Y.Z" in the footer.
+APP_VERSION = "2.0.0"
+
 # req 3 (health): supported formats advertised to clients. Additive key — the
 # existing /health contract asserts only status + max_upload_mb.
 SUPPORTED_FORMATS = ["epub", "html", "htm", "md", "markdown", "txt", "log",
@@ -623,10 +626,10 @@ def health():
     if not _cjk_fonts_present():
         problems.append("CJK fonts missing (fc-list found none)")
     body = {"status": "ok", "max_upload_mb": MAX_UPLOAD_MB,
-            "supported_formats": SUPPORTED_FORMATS}
+            "supported_formats": SUPPORTED_FORMATS, "version": APP_VERSION}
     if problems:
         body = {"status": "degraded", "max_upload_mb": MAX_UPLOAD_MB,
-                "supported_formats": SUPPORTED_FORMATS, "problems": problems}
+                "supported_formats": SUPPORTED_FORMATS, "version": APP_VERSION, "problems": problems}
         return jsonify(body), 503
     return jsonify(body), 200