feat(chrome): add local model support (Ollama, LM Studio)

[chrisqianz]

Problem Description

When trying to use local models (like Ollama, LM Studio, llama.cpp) in the Chrome extension, users encounter the error:

Error: No API key for provider: Local

Even after adding a local provider through Settings → API Keys & OAuth, the system still prompts for an API key when sending messages.

Root Cause

The system architecture requires API keys for all providers, but local models like Ollama don't need API keys.

Changes Made

1. API Keys & OAuth Settings (ApiKeysOAuthTab.ts)

• Added "Custom Providers" section with buttons to add Ollama, LM Studio, OpenAI Compatible providers
• Uses existing CustomProviderDialog component

2. Sidepanel (sidepanel.ts)

• getProvidersWithKeys() - Now includes custom provider names
• hasAnyApiKey() - Now checks custom providers
• getApiKey() - Returns custom provider credentials (or empty string if no API key)
• onApiKeyRequired() - Skips API key dialog for custom providers

3. API Key Dialog (ApiKeyOrOAuthDialog.ts)

• Now checks both providerKeys and customProviders when polling for key existence

Testing

1. Add Ollama provider via Settings → API Keys & OAuth → Add Ollama
2. Configure Ollama URL (e.g., http://localhost:11434)
3. Select a local model from the model selector
4. Send a message - should work without API key prompt

Tags

• chrome-extension
• local-models
• ollama