fix(api): verify writes by read-back; honest save feedback

Two real problems fixed:

1. The API reported 'written: true' based on the dongle's echo, but the
   dongle can echo a write without forwarding it to the inverter. Now the
   API reads the register back after writing and only reports success when
   the value actually stuck. Invalid values (e.g. hour=30) now correctly
   return 502 'Modbus error response: code 53' instead of false success.

2. The schedule save button gave no visible feedback: the message element
   was at the bottom of the page (below the fold) and the inputs were never
   reloaded after save. Added a dedicated #schedule-msg element inside the
   schedule card, and reload the authoritative inverter values after save so
   the inputs reflect what actually stuck.

Author: jmewing

api/__init__.py

@@ -1168,6 +1168,7 @@ def api_automation_registers():
     AUTOMATION_TYPES,
     ALL_CONDITION_KINDS,
     SETTING_NAME_TO_REGISTER,
+    _read_holding_register,
 )
 
 
@@ -1674,7 +1675,31 @@ def api_holding_put(name: str, body: HoldingUpdate):
         time.sleep(0.7)
     if not ok:
         raise HTTPException(502, f"Failed to write {name}: {msg}")
-    logger.info("Wrote holding register %s (address %d) = %d", name, reg, raw_value)
+
+    # VERIFY: the dongle can echo a write without actually forwarding it to
+    # the inverter. Read the register back and confirm it stuck before
+    # reporting success. This is the difference between "the dongle ACKed"
+    # and "the inverter actually applied it".
+    verified = False
+    for attempt in range(4):
+        rok, rval, rmsg = _read_holding_register(
+            dongle["dongle_host"],
+            dongle["dongle_port"],
+            dongle["datalog_serial"],
+            dongle["inverter_serial"],
+            reg,
+        )
+        if rok and rval == raw_value:
+            verified = True
+            break
+        time.sleep(0.5)
+    if not verified:
+        raise HTTPException(
+            502,
+            f"Write to {name} not confirmed on inverter (echoed but read-back mismatch)",
+        )
+
+    logger.info("Wrote holding register %s (address %d) = %d (verified)", name, reg, raw_value)
     return {"name": name, "address": reg, "raw": raw_value, "written": True, "message": msg}
 
 

api/static/index.html

@@ -289,6 +289,7 @@ <h3>Timer Schedule</h3>
             <button class="btn" id="btn-save-schedule">Save Schedule</button>
           </div>
           <div id="schedule-editor"></div>
+          <div id="schedule-msg" style="margin-top:0.75rem; font-size:0.9rem; font-weight:600;"></div>
         </div>
       </div>
 
@@ -1035,7 +1036,7 @@ <h4 style="margin-bottom:0.5rem;">${g.title}</h4>
   });
 }
 async function saveSchedule() {
-  const msg = document.getElementById('auto-msg');
+  const msg = document.getElementById('schedule-msg') || document.getElementById('auto-msg');
   const el = document.getElementById('schedule-editor');
   if (!el) return;
   const values = {};
@@ -1088,6 +1089,9 @@ <h4 style="margin-bottom:0.5rem;">${g.title}</h4>
       msg.textContent = `Value set — ${written} register${written === 1 ? '' : 's'} written.`;
       msg.style.color = 'var(--green-color)';
     }
+    // Reload the authoritative inverter values so the inputs reflect what
+    // actually stuck (the dongle can echo a write without applying it).
+    try { await loadAutomationSettings(); renderSchedule(); } catch (e) {}
   } catch (e) {
     msg.textContent = 'Error setting value: ' + e.message; msg.style.color = 'var(--red-color)';
   }