Clamp position precision on public / known-keys (#10665)

* Clamp position precision on public / known-keys (Compliance)

* Fix review comments: bounds check, all-channel precision clamp, disabled channel guard

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* Refactor position precision comments for clarity and update channel configuration handling in AdminModule

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

src/modules/AdminModule.cpp

@@ -2,6 +2,7 @@
 #include "Channels.h"
 #include "MeshService.h"
 #include "NodeDB.h"
+#include "PositionPrecision.h"
 #include "PowerFSM.h"
 #include "RTC.h"
 #include "SPILock.h"
@@ -1157,7 +1158,26 @@ void AdminModule::handleSetChannel(const meshtastic_Channel &cc)
     if (channels.ensureLicensedOperation()) {
         sendWarning(licensedModeMessage);
     }
+    // Refresh derived state (primaryIndex in particular) BEFORE the precision clamp below. usesPublicKey()
+    // resolves a secondary channel's key against the primary, so it must see the post-update primaryIndex;
+    // running the clamp first could evaluate secondaries against the previous primary and skip the clamp/warning.
     channels.onConfigChanged(); // tell the radios about this change
+
+    // Persist the public-key precision clamp for all channels that may be affected (e.g. secondaries
+    // that inherit a now-public primary key) and warn the client once if anything was coarsened.
+    bool clamped = false;
+    for (uint8_t i = 0; i < channels.getNumChannels(); i++) {
+        meshtastic_Channel &ch = channels.getByIndex(i);
+        if (ch.role == meshtastic_Channel_Role_DISABLED || !ch.settings.has_module_settings)
+            continue;
+        uint32_t allowed = getPositionPrecisionForChannel(i);
+        if (allowed != ch.settings.module_settings.position_precision) {
+            ch.settings.module_settings.position_precision = allowed;
+            clamped = true;
+        }
+    }
+    if (clamped)
+        sendWarning(publicChannelPrecisionMessage);
     saveChanges(SEGMENT_CHANNELS, false);
 }