v0.18.0

## Docker Images

Published to Docker Hub:

- `mahimairaja/voicegateway:0.18.0`
- `mahimairaja/voicegateway:latest`
- `mahimairaja/voicegateway-dashboard:0.18.0`
- `mahimairaja/voicegateway-dashboard:latest`

Built for `linux/amd64` and `linux/arm64`.

## Quick Start

```bash
docker run -p 8080:8080 \
  -v $(pwd)/voicegw-data:/data \
  mahimairaja/voicegateway:0.18.0
```

See [docs.voicegateway.dev](https://docs.voicegateway.dev) for full documentation.


## What's Changed
* feat(billing): metering + rating layer (rate card, write-time rating, /v1/billing, voicegw prices) by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/113
* feat(billing): re-rate fleet rows on ingest against the collector's card by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/114
* feat(billing): store rated_price_usd + rate_rule in ClickHouse by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/115
* feat(billing): read billable usage from ClickHouse when CH-backed by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/116
* feat(billing): persist rate-card overrides in a DB store, editable via CLI by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/117
* feat(billing): edit rate-card DB overrides over HTTP by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/118
* feat(dashboard): add Rate card page (view + edit DB overrides) by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/119
* docs(billing): drop stale follow-up language now that editing shipped by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/120
* feat(brand): new gauge logo across engine surfaces by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/121
* feat(brand): refresh README banner with the gauge logo; drop dead wordings assets by @mahimairaja in https://github.com/mahimailabs/voicegateway/pull/122


**Full Changelog**: https://github.com/mahimailabs/voicegateway/compare/v0.17.0...v0.18.0