fix(tesla): make PrivateKeyError a LibraryError, not TeslaFleetError

A key-file failure is local to this library, not an upstream Fleet API
error, so it belongs with SigningDisabled under LibraryError.

Claude-Session: https://claude.ai/code/session_01D7girHWFLWBu78by9NL3qE

Author: Bre77

README.md

@@ -178,8 +178,9 @@ owner-writable only (`0600`) from the start, with no write-then-chmod window,
 and concurrent creators fall back to reading the file that won the create
 race. If an existing key file can't be read, isn't valid PEM, is
 password-encrypted, or is the wrong key type, both raise `PrivateKeyError`
-(a `TeslaFleetError`) with a `reason` of `"unreadable"`, `"malformed"`,
-`"encrypted"`, or `"wrong_type"`.
+(a `LibraryError`, not a `TeslaFleetError` - it's a local key-file failure,
+not an upstream Fleet API error) with a `reason` of `"unreadable"`,
+`"malformed"`, `"encrypted"`, or `"wrong_type"`.
 
 `VehicleBluetooth` keeps a held BLE connection alive during idle periods by
 default with a passive GATT read about every 20 seconds. Pass

tesla_fleet_api/exceptions.py

@@ -404,23 +404,6 @@ class DeviceUnexpectedResponse(TeslaFleetError):
     status = 540
 
 
-class PrivateKeyError(TeslaFleetError):
-    """An existing private key file could not be loaded as a usable key.
-
-    Raised by ``Tesla.get_private_key``/``get_rsa_private_key`` only for a
-    known-existing key file's read/parse failure - key generation and the
-    O_EXCL create-race fallback keep raising their original exceptions.
-    ``reason`` is one of ``"unreadable"`` (I/O failure), ``"malformed"`` (not
-    valid PEM), ``"encrypted"`` (PEM requires a passphrase), or
-    ``"wrong_type"`` (loaded key is not the expected type).
-    """
-
-    def __init__(self, reason: str, message: str) -> None:
-        self.reason = reason
-        self.message = message
-        super().__init__()
-
-
 class LibraryError(Exception):
     """Errors related to this library."""
 
@@ -442,6 +425,25 @@ def __init__(self) -> None:
         )
 
 
+class PrivateKeyError(LibraryError):
+    """An existing private key file could not be loaded as a usable key.
+
+    Raised by ``Tesla.get_private_key``/``get_rsa_private_key`` only for a
+    known-existing key file's read/parse failure - key generation and the
+    O_EXCL create-race fallback keep raising their original exceptions.
+    ``reason`` is one of ``"unreadable"`` (I/O failure), ``"malformed"`` (not
+    valid PEM), ``"encrypted"`` (PEM requires a passphrase), or
+    ``"wrong_type"`` (loaded key is not the expected type). A local key-file
+    failure, not an upstream Fleet API error, so this subclasses
+    ``LibraryError`` rather than ``TeslaFleetError``.
+    """
+
+    def __init__(self, reason: str, message: str) -> None:
+        self.reason = reason
+        self.message = message
+        super().__init__(message)
+
+
 class SignedCommandRequired(TeslaFleetError):
     """The requested action requires a signed command; the unsigned cloud API cannot actuate it.