Update docs for auth, time, discovery, and history changes

Requirements.md

@@ -34,15 +34,19 @@ Function names below are C++ references. Rust naming/layout may differ, but the
   - sync-request cadence 15 s while unsynced.
 - Receiver behavior:
   - decode/reconstruct sparse timestamps.
-  - ACK each decoded batch promptly.
+  - ACK accepted batches promptly.
+  - reject unknown/mismatched sender identities before ACK and before SD/MQTT/web updates.
   - update MQTT, web status, SD logging.
 - Persistence:
   - Wi-Fi/MQTT/NTP/web credentials in Preferences namespace `dd3cfg`.
+- Web auth defaults:
+  - `WEB_AUTH_REQUIRE_STA=true`
+  - `WEB_AUTH_REQUIRE_AP=true`
 - Web and display time rendering:
   - local timezone from `TIMEZONE_TZ`.
 - SD logging:
-  - CSV columns include both `ts_utc` and `ts_hms_utc`.
-  - history parser expects this current layout.
+  - CSV columns include both `ts_utc` and `ts_hms_local`.
+  - history parser supports both current (`ts_utc,ts_hms_local,p_w,...`) and legacy (`ts_utc,p_w,...`) layouts.
 
 ## 3. Protocol and Data Contracts
 
@@ -58,7 +62,14 @@ Function names below are C++ references. Rust naming/layout may differ, but the
 - Timestamp constraints:
   - receiver rejects decoded data whose timestamps are below `MIN_ACCEPTED_EPOCH_UTC`
 - CSV header (current required layout):
-  - `ts_utc,ts_hms_utc,p_w,p1_w,p2_w,p3_w,e_kwh,bat_v,bat_pct,rssi,snr,err_m,err_d,err_tx,err_last`
+  - `ts_utc,ts_hms_local,p_w,p1_w,p2_w,p3_w,e_kwh,bat_v,bat_pct,rssi,snr,err_m,err_d,err_tx,err_last`
+- Home Assistant discovery contract:
+  - topic: `homeassistant/sensor/<device_id>/<key>/config`
+  - `unique_id`: `<device_id>_<key>`
+  - `device.identifiers`: `["<device_id>"]`
+  - `device.name`: `<device_id>`
+  - `device.model`: `DD3-LoRa-Bridge`
+  - `device.manufacturer`: `AcidBurns`
 
 ## 4. Module and Function Requirements
 
@@ -126,8 +137,9 @@ Function names below are C++ references. Rust naming/layout may differ, but the
   - configure NTP servers and timezone env.
 - `uint32_t time_get_utc()`
   - return epoch or `0` when not plausible.
+  - updates "clock plausible" state independently from sync state.
 - `bool time_is_synced()`
-  - sync status helper.
+  - true only after explicit sync signals (NTP callback/status or trusted `time_set_utc`).
 - `void time_set_utc(uint32_t)`
   - set system time and sync flags.
 - `void time_get_local_hhmm(char*, size_t)`
@@ -136,6 +148,8 @@ Function names below are C++ references. Rust naming/layout may differ, but the
 - `uint32_t time_get_last_sync_age_sec()`
 - Internal behavior-critical helpers:
   - `note_last_sync`
+  - `mark_synced`
+  - `ntp_sync_notification_cb`
   - `ensure_timezone_set`
 
 ## `src/lora_transport.cpp`
@@ -202,12 +216,14 @@ Function names below are C++ references. Rust naming/layout may differ, but the
   - `fault_text`
   - `mqtt_connect`
   - `publish_discovery_sensor`
+  - discovery payload uses canonical device identity fields and `manufacturer=AcidBurns`
 
 ## `src/wifi_manager.cpp`
 
 - `void wifi_manager_init()`
 - `bool wifi_load_config(WifiMqttConfig&)`
 - `bool wifi_save_config(const WifiMqttConfig&)`
+  - returns `false` when any Preferences write/verify fails.
 - `bool wifi_connect_sta(const WifiMqttConfig&, uint32_t timeout_ms)`
 - `void wifi_start_ap(const char*, const char*)`
 - `bool wifi_is_connected()`
@@ -223,7 +239,7 @@ Function names below are C++ references. Rust naming/layout may differ, but the
   - `fault_text`
   - `ensure_dir`
   - `format_date_utc`
-  - `format_hms_utc`
+  - `format_hms_local`
 
 ## `src/display_ui.cpp`
 
@@ -395,6 +411,7 @@ These functions define end-to-end firmware behavior and must have equivalents:
   - bootstrap guardrail, retry counts, schedule intervals, min accepted epoch.
 - Preserve CSV output layout exactly:
   - consumers (history parser and external tooling) depend on it.
+  - preserve reader compatibility for both current and legacy layouts.
 - Preserve enum meanings:
   - `FaultType`, `RxRejectReason`, `LoraMsgKind`.
 
@@ -415,5 +432,5 @@ Suggested Rust primitives:
 - Duplicate batch handling updates counters and suppresses duplicate publish/log.
 - Web UI shows `epoch (HH:MM:SS TZ)` local time.
 - SD CSV header/fields match expected order.
-- History endpoint reads only current CSV layout successfully.
+- History endpoint reads current and legacy CSV layouts successfully.
 - MQTT state/fault payload fields match existing names and semantics.