fix ntpserver default

src/Agent/AutopilotMonitor.Agent/buildcounter.txt

@@ -1 +1 @@
-731
+732

src/Backend/AutopilotMonitor.Functions/DataAccess/TableStorage/TableConfigRepository.cs

@@ -464,7 +464,7 @@ namespace AutopilotMonitor.Functions.DataAccess.TableStorage
                 RebootDelaySeconds = entity.GetInt32("RebootDelaySeconds"),
                 EnableGeoLocation = entity.GetBoolean("EnableGeoLocation"),
                 EnableTimezoneAutoSet = entity.GetBoolean("EnableTimezoneAutoSet"),
-                NtpServer = entity.GetString("NtpServer") ?? "",
+                NtpServer = entity.GetString("NtpServer") ?? "time.windows.com",
                 EnableImeMatchLog = entity.GetBoolean("EnableImeMatchLog"),
                 LogLevel = entity.GetString("LogLevel"),
                 MaxBatchSize = entity.GetInt32("MaxBatchSize"),

tasks/lessons.md

@@ -14,6 +14,11 @@
 
 ## Common Mistakes
 
+### Table Storage mapping defaults must match domain defaults (2026-03-31)
+**What went wrong:** Added `NtpServer` mapping with `?? ""` fallback. Existing tenants had no value stored → got empty string instead of `"time.windows.com"` → agent NTP check broke.
+**Rule:** When adding missing Table Storage read mappings, the `??` fallback MUST match the domain/model default (check `AgentConfigResponse`, `GetAgentConfigFunction`, or the property initializer). Never use empty string as fallback for fields that have a meaningful default.
+**Severity:** PRODUCTION — silently breaks agent functionality for all existing tenants.
+
 ### PowerShell scripts deployed via Intune MUST be pure ASCII (2026-03-30)
 **What went wrong:** Em-dash characters `—` (U+2014) and Unicode symbols (✓, →, ✗) in Bootstrap .ps1 scripts caused cascading PowerShell parse errors in production. The IME (Intune Management Extension) uses PowerShell 5.1 which reads scripts without BOM as ANSI — multi-byte UTF-8 chars get corrupted.
 **Rule:** ALL `.ps1` files under `scripts/Bootstrap/` (and any other scripts deployed via Intune) MUST contain only ASCII characters (0x00-0x7F). No em-dashes, no Unicode symbols, no special quotes. Use `-` instead of `—`, `[OK]` instead of `✓`, etc.