protondrive: align move crypto and revision fallback with the SDK

[tdawe1]

Support the rclone Proton Drive backend update by aligning the bridge move/upload compatibility behavior with the current Proton Drive SDK.

The main issue here was that move-related flows no longer matched the newer SDK behavior closely enough. In practice, that meant moves could fail or leave moved folders containing files in a bad state.

This change updates the bridge to:

• preserve the original node passphrase session key when re-encrypting moved folders, matching the current SDK behavior
• send optional move signature fields only when the SDK would send them
• fall back cleanly from newer volume-based compatibility helpers to the older share-based helpers when the preferred method exists but has an incompatible transitional signature
• tolerate missing revision-verification helpers in the compatibility layer so the supported v2 path can still work without reviving deprecated API behavior

Testing:

go test ./... -run '^(TestReencryptKeyPacketPreservesSessionKey|TestSetMoveLinkSignatureAddressCompat|TestApplyMoveRequestSignaturesForSignedNode|TestApplyMoveRequestSignaturesForAnonymousNode|TestBuildVerificationTokenXorsWithEncryptedBlock|TestBuildVerificationTokenKeepsTailWhenBlockShorter|TestGetRevisionVerificationCompatPrefersVolumeRoute|TestGetRevisionVerificationCompatFallsBackToShareRoute|TestGetRevisionVerificationCompatFallsBackWhenVolumeRouteSignatureIsIncompatible|TestGetRevisionVerificationCompatHandlesInvalidSignature|TestGetRevisionVerificationCompatHandlesPanickingMethod|TestGetRevisionVerificationCompatAllowsMissingMethods|TestMoveLinkCompatPrefersVolumeRoute|TestMoveLinkCompatFallsBackToShareRoute|TestMoveLinkCompatFallsBackWhenVolumeRouteSignatureIsIncompatible|TestMoveLinkCompatHandlesInvalidSignature|TestMoveLinkCompatHandlesPanickingMethod|TestUploadBlockWithClientDelegatesSingleCall)$' -count=1

GOWORK=/tmp/proton-sdk-work/go.work \
PROTON_API_BRIDGE_APP_VERSION='web-drive@5.2.0+af66c8fa' \
PROTON_API_BRIDGE_DRIVE_SDK_VERSION='js@5.2.0+af66c8fa' \
go test ./... -run '^(TestCreateAndMoveAndDeleteFolder|TestCreateAndMoveAndDeleteFolderWithAFile|TestCreateAndMoveAndDeleteAFileOneLevelFromRoot)$' -count=1 -v

This PR should be reviewed on top of the companion go-proton-api SDK base compatibility PR.

Companion SDK base PR: rclone/go-proton-api#5