geolocation: add result destination for LocationOffsets

[ben-dz]

Resolves: #3468

Summary of Changes

• Rust SDK SetResultDestinationCommand that builds the onchain transaction with user PDA + probe account metas
• CLI user set-result-destination --destination <host:port> (or --clear) with client-side validation of IP routability and domain format before transaction submission
• Display result_destination in user get output (shows "none" when unset)
• Go SDK ResultDestination string field on GeolocationUser with backwards-compatible deserialization (old accounts default to "")
• Subcommand registration in the geolocation CLI binary

Stacked on #3501 which adds the onchain SetResultDestination instruction and result_destination field.

Diff Breakdown

Category	Files	Lines (+/-)	Net
Core logic	3	+425 / -8	+417
Scaffolding	6	+13 / -0	+13
Tests	1	+49 / -2	+47

Core logic is the CLI command (290 lines including validation + tests), Rust SDK command (118 lines), and Go SDK deserialization. Scaffolding is trait wiring and subcommand registration.

Key files (click to expand)

• smartcontract/cli/src/geolocation/user/set_result_destination.rs — CLI command with clap args, client-side host:port validation (IP routability + domain format per RFC 1035), mock tests for set/clear/invalid inputs
• smartcontract/sdk/rs/src/geolocation/geolocation_user/set_result_destination.rs — Rust SDK command: validates code, derives user PDA, passes probe account metas to execute_transaction
• sdk/geolocation/go/state.go — ResultDestination string field, serialize/deserialize with try-decode-default for backwards compat
• sdk/geolocation/go/state_test.go — round-trip and backwards-compat tests (truncated data defaults to empty)
• smartcontract/cli/src/geoclicommand.rs — set_result_destination trait method + impl

Testing Verification

• CLI mock tests: set destination, clear, missing destination flag, 9 invalid destination cases (private IPs, bad ports, malformed domains)
• Go SDK: round-trip test with non-empty destination, empty-targets test, backwards-compat test (truncated data)
• All tests pass: 289 CLI, 165 SDK, 82 geolocation, Go SDK green