feat: add DotHoosh (دات‌هوش) provider

[Alirezajalilii]

Description

Adds DotHoosh (دات‌هوش), an Iranian AI gateway billed in Toman from a prepaid wallet, as an OpenAI-compatible provider (provider: dothoosh, default apiBase https://gateway.dothoosh.com/v1/), wired the same way as nebius: core class, LLM registry, config-types, openai-adapters, the Add Model GUI entry with eight model presets, the VS Code config schema, logo, and a docs page.

The docs page also shows how to use DotHoosh's Claude models through the existing anthropic provider with apiBase: https://gateway.dothoosh.com/anthropic/v1/ (Continue's Anthropic client sends x-api-key, which that endpoint requires).

DotHoosh is not added to PROVIDER_SUPPORTS_IMAGES (its routes are text-only today).

Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Tests

• core/llm/llms/OpenAI-compatible.vitest.ts: 14 new dothoosh cases (218 pass).
• tsc --noEmit -p core: clean. Prettier: clean on changed files.

[github-actions]

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[Alirezajalilii]

I have read the CLA Document and I hereby sign the CLA