fix: include long turbo modem preset

[fresh3nough]

Description

Add the Long Turbo modem preset to the LoRa modem preset list by updating protobufs and verifying availability in validation.

Related Issues

Fixes #999

Steps to Reproduce

1. Connect to a node running firmware 2.7.17 or newer.
2. Go to Radio Config > LoRa.
3. Open the Modem Preset list.
4. Observe that Long Turbo is missing.

Changes Made

• bump @meshtastic/protobufs to 2.7.18 (includes LONG_TURBO)
• add a lora config test that asserts LONG_TURBO is present
• update pnpm lockfile

Testing Done

• Pre-fix check (main): node -e "import('@meshtastic/protobufs').then(m=>console.log(Object.prototype.hasOwnProperty.call(m.Config.Config_LoRaConfig_ModemPreset,'LONG_TURBO'))).catch(err=>{console.error(err);process.exit(1);})" (result: false)
• Post-fix check (branch): node -e "import('@meshtastic/protobufs').then(m=>console.log(Object.prototype.hasOwnProperty.call(m.Config.Config_LoRaConfig_ModemPreset,'LONG_TURBO'))).catch(err=>{console.error(err);process.exit(1);})" (result: true)
• pnpm --filter @meshtastic/web test -- --run (fails: @meshtastic/transport-node-serial src/transport.test.ts | TransportNodeSerial > emits DeviceDisconnected when the underlying link drops)

Screenshots (if applicable)

N/A

Checklist

• Code follows project style guidelines
• Documentation has been updated or added
• Tests have been added or updated
• All i18n translation labels have been added (not applicable)

cc @philon-

Co-Authored-By: Warp agent@warp.dev

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[danditomaso]

Looks good