sdk/geolocation: add Go write SDK for add/remove target operations

[ben-dz]

Resolves: #3557

Summary of Changes

• New Go write SDK for the geolocation program focused on target management: instruction builders for AddTarget and RemoveTarget, plus a transaction executor.
• Instruction builders follow the telemetry write SDK pattern: *InstructionConfig struct + Validate() + Build*Instruction() returning a self-contained solana.Instruction, using near/borsh-go to match the Rust program's Borsh layout.
• User lifecycle (CreateGeolocationUser, UpdateGeolocationUser, DeleteGeolocationUser) and SetResultDestination are deferred to a follow-on PR (sdk/geolocation: add Go write SDK for user lifecycle and result destination #3567) to keep this reviewable — my immediate consumer only needs add/remove targets.

Diff Breakdown

Category	Files	Lines (+/-)	Net
Core logic	5	+475 / -0	+475
Tests	4	+389 / -0	+389

Pure-additive new package; ~45% of the diff is tests.

Testing Verification

• Borsh serialization tests pin discriminator bytes, field ordering, and IP/port/target-pk layout against the Rust program's expected layout for Add/Remove.
• Private-IP validation covers all reserved ranges (10/8, 172.16/12, 192.168/16, 127/8, 0.0.0.0) for outbound target types.
• Account-meta ordering verified against the Rust SDK command builders.
• Executor error paths covered: missing signer, missing program ID.

[vihu]

LGTM