feat(ui-core,ui-lvgl): remote admin session in the Core, L2 admin screen

AdminSession (login with saved password, CLI round trips, timeouts, field
table, typed values) moves into ui-core; UiCore offers login answers and
CLI replies to it first. ui-new's Tools > Admin becomes a view over it.
L2: node detail > Admin with tabs and per-field popups.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/development/l2-hardware-checklist.md

@@ -52,6 +52,20 @@ Confirmed: green dot inside the ring, waypoints much better, download works, set
 - [ ] L1 (ui-new): Messages > Channels add / edit / delete / mute / pin still work (now through the shared ChannelControl)
 - [ ] L1: deleting a contact from the app still unpins it from the dial and clears its mute / melody (cleanup moved into the Core)
 
+## New: Repeater admin (2026-09-25)
+- [ ] Nearby > a repeater or room server you have in contacts > "Admin" (the Fav button is just a star there)
+- [ ] First time: password field + keyboard; wrong password → "Login failed", back on the node; right one → tabs System / Radio / Routing / Actions
+- [ ] Next time: logs in by itself with the saved password (no keyboard); a node you just used opens straight away
+- [ ] Out of range: "No answer to the login" after a while, and the saved password is forgotten (asks again next time)
+- [ ] Name / Owner info: "Reading..." then a text field with the current value; ✓ sends it, reply popup "OK"
+- [ ] Admin password: set a new one → the saved password follows (next login works without typing)
+- [ ] Routing > Repeat switch; Advert interval / Flood advert / Max hops with − / +; Radio > SF / Bandwidth / Coding rate choices, Frequency typed, TX power − / +
+- [ ] Actions: Send advert / zero-hop / Sync clock give a reply; Reboot and Start OTA ask first (red button)
+- [ ] Custom command: e.g. `ver`, `neighbors` (long replies scroll)
+- [ ] "Reading... (tap to stop)" stops waiting when tapped
+- [ ] Room server login from the phone app / L1 still works while this exists (only admin logins go to the new session)
+- [ ] L1 (ui-new): Tools > Admin works as before (login, saved password, typed values, confirm reboot); it now also skips the login for the node you just used
+
 ## Basics after the_mesh moved to PSRAM (`MESH_IN_PSRAM`)
 - [ ] Boots normally, contacts and channels are all there
 - [ ] Messages arrive and send (channel + DM), delivery ticks work

docs/development/ui-core.md

@@ -110,7 +110,7 @@ call the same ones, so e.g. "marking a channel read" has one implementation.
 
 ### 5. Declarative settings schema
 
-`ui-core/SettingsSchema.h` holds three pages -- navigation (trail, live share, arrival alert, units), display & power (brightness, screen off, wake on message, battery shutdown, GPS power saving, time zone) and messages & contacts (DM resends, contact expiry, favourites first). An entry is a one-byte index by default, or a `values` table over a 1/2/4-byte field (seconds, millivolts, an hour offset, `{1, 0}` for a field stored inverted); side effects run through `UiCore` (`applyGpsInterval()`, `host()->applyDisplayPrefs()`). ui-lvgl renders each page; ui-new still uses its own screens. Radio settings are not schema rows (preset list, typed frequency, radio side effects): `ui-core/RadioControl.h` applies them (`applyParams`, `applyTxPower`, `applyApc`, presets = built-ins + user slots) for both ui-new's Settings > Radio and ui-lvgl's Radio screen. Channel management is `ui-core/ChannelControl.h` (`chanctl::`): add Public / Hashtag / Private (passphrase or 32-hex key), rename, delete, notifications / favourite / scope, and `onRemoved()` -- the cleanup of every channel-keyed pref, run by `UiCore::onChannelRemoved` whoever deleted the channel (this device or the app); contacts get the same through `UiCore::cleanupContactPrefs`. Favourites dial slots: `ui-core/Favourites.h`.
+`ui-core/SettingsSchema.h` holds three pages -- navigation (trail, live share, arrival alert, units), display & power (brightness, screen off, wake on message, battery shutdown, GPS power saving, time zone) and messages & contacts (DM resends, contact expiry, favourites first). An entry is a one-byte index by default, or a `values` table over a 1/2/4-byte field (seconds, millivolts, an hour offset, `{1, 0}` for a field stored inverted); side effects run through `UiCore` (`applyGpsInterval()`, `host()->applyDisplayPrefs()`). ui-lvgl renders each page; ui-new still uses its own screens. Radio settings are not schema rows (preset list, typed frequency, radio side effects): `ui-core/RadioControl.h` applies them (`applyParams`, `applyTxPower`, `applyApc`, presets = built-ins + user slots) for both ui-new's Settings > Radio and ui-lvgl's Radio screen. Channel management is `ui-core/ChannelControl.h` (`chanctl::`): add Public / Hashtag / Private (passphrase or 32-hex key), rename, delete, notifications / favourite / scope, and `onRemoved()` -- the cleanup of every channel-keyed pref, run by `UiCore::onChannelRemoved` whoever deleted the channel (this device or the app); contacts get the same through `UiCore::cleanupContactPrefs`. Favourites dial slots: `ui-core/Favourites.h`. Remote admin is `ui-core/AdminSession.h` (`UiCore::admin`): login with the saved password (forgotten on a wrong password or a silent timeout), CLI round trips with timeouts, the field table (`admin::`), typed values; results come out one at a time through `take()`. `UiCore` offers login answers and CLI replies to it first; only room logins it wasn't waiting for reach the frontend. ui-new's Tools > Admin and ui-lvgl's Admin screen are views over it.
 
 Replaces the per-item code in `SettingsScreen`: