Refine Wi-Fi, mDNS, and terminal lifecycles

- Stage disabled station profile edits without restarting the radio
- Make mDNS initialization failure-isolated and reannounce in place
- Document deferred admin actions and explicit browser disconnect
  behavior

docs/agent/current-state.md

@@ -21,6 +21,7 @@ Based on checked-in source plus `README.md` and `docs/roadmap.md`:
 - UART and admin-SSH completion formatter buffers were reduced from 2 KiB to 1 KiB each; current worst-case output is 890 bytes and overflow remains fail-closed.
 - Linked RAM fell from 99,508 to 92,188 bytes (7,320 bytes). PSRAM placement of serial payloads additionally removes about 24 KiB of normal internal-heap pressure on the target.
 - `pio run` passes. A preliminary target run reports significantly more free memory and stable, improved operation after these changes. This is useful evidence but not completion of Phase 8C validation.
+- The reviewed mDNS-enabled build uses 94,532 bytes of linked static RAM, 2,344 bytes above the earlier 92,188-byte baseline, and 1,599,765 bytes of flash. Minimizing the managed component saved 112 bytes of linked RAM and about 5.9 KiB flash versus the first mDNS build. Its 4 KiB task stack remains internal, while checked-in settings move general mDNS allocations to PSRAM and disable unused browse, component CLI, AP/ETH, and multiple-instance features. Runtime heap impact still requires target measurement.
 - Remaining targeted checks include stored/migrated/recovered user-database mutations, USB enumeration, HTTPS start/stop failure recovery where injectable, SSH initialization/login, completion display, and sustained multi-transport serial traffic while checking `memory` telemetry.
 
 ## Clearly incomplete or transitional areas
@@ -49,10 +50,10 @@ These observations should be checked when touching the relevant area; they are n
 - **Objective:** Announce a configurable `sak-<suffix>.local` hostname through mDNS when Wi-Fi STA has an IPv4 address, without changing the Wi-Fi NVS blob schema.
 - **Relevant files:** `src/mdns_config.{c,h}`, `src/mdns_service.{c,h}`, `src/mdns_console.{c,h}`, `src/wifi_manager.{c,h}`, `src/main.c`, `src/CMakeLists.txt`, `src/idf_component.yml`, `dependencies.lock`, completion and command documentation.
 - **Findings:** `wifi_manager` already serializes all meaningful STA transitions through its permanent task; callbacks only enqueue events. This is the appropriate lifecycle owner for mDNS, while a separate configuration module preserves the existing `wifi_app/config` wire format.
-- **Decision:** Persist a fixed v1 record under `mdns_cfg/config`, separate from Wi-Fi configuration. Defaults derive a safe lower-case hexadecimal suffix from the STA MAC. The manager starts mDNS after validating `IP_EVENT_STA_GOT_IP`, stops it on IPv4 loss, STA disconnect, and radio stop, and performs online reannouncements requested after configuration changes. mDNS errors are logged but cannot fail Wi-Fi, UART0, UART1, or native USB.
-- **Changes completed:** Added the `espressif/mdns` managed dependency (resolved to 1.12.0 on IDF 5.5), mDNS config/service/console modules, `mdns status|suffix|save|load|defaults|reset`, completion, CMake integration, and command/architecture documentation. `pio run` passes.
+- **Decision:** Persist a fixed v1 record under `mdns_cfg/config`, separate from Wi-Fi configuration. Defaults derive a safe lower-case hexadecimal suffix from the STA MAC. The manager initializes mDNS at most once after validating `IP_EVENT_STA_GOT_IP`; the managed component's own handlers withdraw/restore the STA responder across connectivity changes, and online hostname changes use `mdns_hostname_set()` without teardown. Initialization failure is latched instead of retried because the resolved upstream 1.12.0 component has an unsafe partial low-memory initialization path. mDNS errors cannot fail Wi-Fi, UART0, UART1, or native USB.
+- **Changes completed:** Added the `espressif/mdns` managed dependency (resolved to 1.12.0 on IDF 5.5), mDNS config/service/console modules, `mdns status|suffix|save|load|defaults|reset`, completion, CMake integration, and command/architecture documentation. Minimized the component to STA-only responder use, moved general allocations to PSRAM, retained the internal task stack, and removed reconnect-time free/reinit churn. Final `pio run` passes at 94,532 bytes linked RAM and 1,599,765 bytes flash.
 - **Remaining work:** Target-hardware verification: associate a station and resolve the default `sak-<mac>.local`; change/save/load a suffix and confirm live reannouncement plus reboot persistence; stop Wi-Fi or remove the STA lease and confirm the record withdraws. Verify serial, native USB, and UART0 remain available if mDNS initialization fails.
-- **Risks / things to remember:** Hostnames are STA-only and are intentionally not announced by fallback AP mode. NVS changes to `mdns_cfg/config` are independent of the unchanged `wifi_app/config` blob.
+- **Risks / things to remember:** Hostnames are STA-only and are intentionally not announced by fallback AP mode. NVS changes to `mdns_cfg/config` are independent of the unchanged `wifi_app/config` blob. mDNS remains allocated after first successful initialization (including its internal 4 KiB task stack) to avoid fragmentation and unsafe repeated initialization; measure free/minimum/largest internal heap and mDNS stack margin during reconnect stress.
 
 ### Handoff template