Adds a first pass at India iSMART support in a separate saic_ismart_client_ng.india module.

What is included:

• India TAP and gateway endpoints for mgindia.co.in
• phone number normalization and stable device id generation
• TAP login request/signature handling
• India gateway request signing headers
• AES-CBC response decrypt helper for encrypted gateway payloads
• vehicle list parsing
• read-only vehicle status request/response codec for TAP protocol 513
• status parsing for doors, windows, lock state, temperatures, fuel/range, odometer, CAN activity, aux battery voltage, handbrake, and similar basic fields

I have intentionally kept this read-only for now. Remote commands should probably come in a separate PR once the status/login path has had more testing.

Validation run locally:

• pytest tests/test_india_api.py -q
• pytest -q --disable-warnings
• ruff check src/saic_ismart_client_ng/india tests/test_india_api.py
• python -m compileall -q src/saic_ismart_client_ng/india tests/test_india_api.py
• git diff --check

All tests pass locally: 33 passed.