Fix question counter daily reset, rate-limit timer, and founding member pricing clarity

- chat-widget: session.count now resets on new UTC day (keeps client in sync with server's daily quota reset)
- chat-widget: fix rate-limit timer — wrong element IDs (neuron-demo-msgs → neuron-demo-messages) and wrong class (.neuron-msg-ai → .demo-msg-ai) meant the countdown never updated
- chat-widget: remove btn.disabled=false that immediately re-enabled the send button after rate-limiting
- main.el: add POST /api/admin/reset-rate-limits endpoint (requires NEURON_ADMIN_TOKEN, deletes all demo_rate_limits rows)
- pricing.el: clarify founding member card — software updates are free forever, inference is pay-per-use at founding member rate

src/main.el

@@ -873,6 +873,32 @@ fn handle_request_inner(method: String, path: String, headers: Map, body: String
         return "{\"rows\":" + ac_resp + "}"
     }
 
+    // ── Admin: reset all demo rate limits ────────────────────────────────────
+    // POST { "admin_token": "<NEURON_ADMIN_TOKEN>" }
+    // Deletes all rows from demo_rate_limits — resets every user's daily quota.
+    if str_eq(path, "/api/admin/reset-rate-limits") {
+        if !str_eq(method, "POST") {
+            return "{\"__status__\":405,\"error\":\"POST required\"}"
+        }
+        let rrl_token_in:  String = json_get(body, "admin_token")
+        let rrl_token_exp: String = env("NEURON_ADMIN_TOKEN")
+        if str_eq(rrl_token_exp, "") {
+            return "{\"__status__\":503,\"error\":\"admin_token_not_configured\"}"
+        }
+        if !str_eq(rrl_token_in, rrl_token_exp) {
+            return "{\"__status__\":401,\"error\":\"unauthorized\"}"
+        }
+        let rrl_sb_url:  String = state_get("__supabase_project_url__")
+        let rrl_sb_key:  String = state_get("__supabase_service_key__")
+        if str_eq(rrl_sb_url, "") || str_eq(rrl_sb_key, "") {
+            return "{\"__status__\":503,\"error\":\"supabase_not_configured\"}"
+        }
+        // DELETE /rest/v1/demo_rate_limits?uid=not.is.null  (all rows)
+        let rrl_url: String = rrl_sb_url + "/rest/v1/demo_rate_limits?uid=not.is.null"
+        let _rrl_resp: String = http_delete_auth(rrl_url, rrl_sb_key, rrl_sb_key)
+        return "{\"ok\":true,\"message\":\"rate limits cleared\"}"
+    }
+
     // ── My plan: server-side waitlist read with JWT verification ─────────────
     // POST { "access_token": "<user_jwt>" }. We verify the JWT via Supabase
     // /auth/v1/user, extract the email, then read the waitlist row with the