1. fix(wifi): Rename old NAN configuration to NAN-Sync
- Rename CONFIG_ESP_WIFI_NAN_ENABLE to CONFIG_ESP_WIFI_NAN_SYNC_ENABLE to indicate
the support for Synchronized NAN (Wi-Fi Aware).
- Because the original flag really controls the synchronized feature set, rename it
to CONFIG_ESP_WIFI_NAN_SYNC_ENABLE so the NAN-Sync and NAN-USD paths can be
selected independently without confusion.
2. Document esp_wifi_start requirement and fix USD examples
3. Rename nan_callbacks to nan_sync_callbacks
4. Remove the discovery_flag, clarify docs for sync vs USD flows, and add USD start/stop APIs
5. Require esp_wifi_start() before USD start
6. docs(nan): add NAN-USD application examples
7. add migration guide and hints for NAN-USD proto field
8. Improve allow_broadcast documentation
9. Add attention to the API esp_wifi_remain_on_channel
10. fix(wifi): align NAN API renames and docs for v6.0
- keep shared APIs under esp_wifi_nan_* while reserving
sync/usd names for mode-specific entry points
- clarify synchronized-cluster scope in headers, docs, and migration notes (EN/zh-CN)
- update examples for renamed helpers and WIFI_NAN_SYNC_CONFIG_DEFAULT()
- rename `wifi_nan_config_t` to `wifi_nan_sync_config_t`
11. Mark NAN-USD as esp-idf experimental feature
Update wifi lib with below -
1. Create NAN Discovery SM for beaconing & cluster formation
2. Create NAN interface for Tx/Rx of beacons & action frames
3. Add commands & events for NAN Services Publish/Subscribe/Followup
4. Add NAN Datapath definitions, Events, Peer structures
5. Support for forming and parsing of Datapath related attributes
6. Modules for NDP Req, Resp, Confirm, Term, Peer management
7. NAN Interface related additions in Datapath, Data Tx Q's
In addition include below changes -
1. Add netif and driver support for NAN Interface
2. Add simple examples for Publisher-Subscriber usecases
3. Add an advanced console example that supports commands
for NAN Discovery, Services & Datapath
4. Add wifi_apps for providing better NAN API's and Peer management
Co-authored-by: Shyamal Khachane <shyamal.khachane@espressif.com>