geolocation: add program scaffolding and ProgramConfig instructions

[nikw9944]

Summary of Changes

• Add the doublezero-geolocation onchain program with InitProgramConfig and UpdateProgramConfig instructions
• Foundation allowlist authorization via CPI to the serviceability program's GlobalState
• Upgrade authority verification for program config initialization and updates
• Borsh-derived instruction enum with pack/unpack serialization
• Workspace and Makefile integration for build, lint, and test

Diff Breakdown

Category	Files	Lines (+/-)	Net
Core logic	12	+609 / -0	+609
Tests	4	+177 / -0	+177
Config/build	5	+93 / -9	+84
Docs	1	+33 / -0	+33

Part 1 of 3 for RFC16 geolocation verification — program scaffolding and ProgramConfig management only; GeoProbe CRUD and parent device instructions follow in subsequent PRs.

Key files (click to expand)

• smartcontract/programs/doublezero-geolocation/src/state/program_config.rs — ProgramConfig account state with Borsh serialization, field-by-field deserialization, and validation
• smartcontract/programs/doublezero-geolocation/src/processors/program_config/update.rs — UpdateProgramConfig processor with upgrade authority verification and partial field updates
• smartcontract/programs/doublezero-geolocation/src/processors/program_config/init.rs — InitProgramConfig processor with PDA creation and upgrade authority check
• smartcontract/programs/doublezero-geolocation/src/serializer.rs — Generic account create/write helpers using doublezero-program-common utilities
• smartcontract/programs/doublezero-geolocation/src/instructions.rs — Borsh-derived GeolocationInstruction enum with 2 variants
• smartcontract/programs/doublezero-geolocation/src/error.rs — GeolocationError enum with thiserror derives and ProgramError conversion
• smartcontract/programs/doublezero-geolocation/src/processors/mod.rs — check_foundation_allowlist shared validation via serviceability CPI

Testing Verification

• 10 unit tests covering instruction pack/unpack roundtrips, PDA determinism, ProgramConfig serialization, error code mappings, and account type validation
• Clippy clean with -Dclippy::all -Dwarnings
• Formatting verified with nightly rustfmt