fix: Handle node public key mismatch and show warning (#1720)

* Handle node public key mismatch and show warning

- Add a mismatchKey flag to Node and MessageTopBar to indicate a public key mismatch.
- Set the public key to a default error value (all zeros) when a node's public key changes.
- Display a warning in the MessageTopBar when a key mismatch is detected in PKC.
- Only clear all nodes when a different mynode number is present.

* feat: Add key mismatch detection to NodeInfoDao

This commit introduces a new feature to the `NodeInfoDao` that detects and handles public key mismatches for existing nodes.

-   A new function `upsertCheckKeyMatch` is added to `NodeInfoDao` that checks for public key changes when upserting a node. If a mismatch is detected, the public key is set to `ERROR_BYTE_STRING`, and a warning is logged.
- The function `upsertCheckKeyMatch` is used instead of `upsert` in `NodeRepository` and in `putAll` inside of `NodeInfoDao`.
-   A new test `testPkcMismatch` is added to `NodeInfoDaoTest` to verify the key mismatch detection.
- Changed `testNodes` to have unique public keys.
- Added `mismatchKey` state to the node model.

* detekt spacing

* Refactor: Correctly handle different node installations in NodeRepository

The logic for detecting different node installations in `NodeRepository.kt` was inverted, this commit fixes the logic to use `!=` instead of `==` to detect if the node number has changed.

app/src/main/java/com/geeksville/mesh/database/entity/NodeEntity.kt

@@ -151,7 +151,7 @@ data class NodeEntity(
 
     val isUnknownUser get() = user.hwModel == MeshProtos.HardwareModel.UNSET
     val hasPKC get() = !user.publicKey.isEmpty
-    val errorByteString: ByteString get() = ByteString.copyFrom(ByteArray(32) { 0 })
+    val errorByteString: ByteString get() = ERROR_BYTE_STRING
 
     fun setPosition(p: MeshProtos.Position, defaultTime: Int = currentTime()) {
         position = p.copy { time = if (p.time != 0) p.time else defaultTime }
@@ -174,6 +174,7 @@ data class NodeEntity(
         fun degD(i: Int) = i * 1e-7
         fun degI(d: Double) = (d * 1e7).toInt()
 
+        val ERROR_BYTE_STRING: ByteString = ByteString.copyFrom(ByteArray(32) { 0 })
         fun currentTime() = (System.currentTimeMillis() / 1000).toInt()
     }