Add a help link and bug-report button to the user navbar

Serves docs/guida-utente.md as plain text at GET /guida (no markdown
rendering, kept simple) and links it from the navbar next to a "Segnala un
bug" button. The bug-report link is a placeholder GitHub issues URL
(REPLACE_ME) until a real repo exists.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/main.py

@@ -95,4 +95,12 @@ async def admin_panel() -> FileResponse:
     return FileResponse("app/static/admin.html", headers=_NO_STORE_HEADERS)
 
 
+@app.get("/guida", include_in_schema=False)
+async def user_guide() -> FileResponse:
+    """Serves docs/guida-utente.md as plain text so it opens inline in the
+    browser (no markdown rendering — keeps this simple), linked from the
+    navbar's help button in app/static/index.html."""
+    return FileResponse("docs/guida-utente.md", media_type="text/plain; charset=utf-8")
+
+
 app.mount("/", StaticFiles(directory="app/static", html=True), name="static")

app/static/index.html

@@ -90,12 +90,12 @@
     border: 1px solid var(--color-border);
   }
 
-  button.link {
+  button.link, a.link {
     width: auto; margin-top: 0; padding: 0; min-height: auto;
     background: none; color: var(--color-muted-foreground); font-weight: 500;
     font-size: 0.85rem; text-decoration: underline;
   }
-  button.link:hover { filter: none; color: var(--color-foreground); }
+  button.link:hover, a.link:hover { filter: none; color: var(--color-foreground); }
 
   .row-between { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
 
@@ -293,6 +293,8 @@
     <span class="brand">PLM Lottery</span>
     <div class="app-navbar-account">
       <span class="name" id="dash-username"></span>
+      <a class="link" href="/guida" target="_blank" rel="noopener">Guida</a>
+      <a class="link" href="https://github.com/REPLACE_ME/plm-lottery/issues/new" target="_blank" rel="noopener">Segnala un bug</a>
       <button class="link" onclick="logout()">Esci</button>
     </div>
   </div>