fix: preserve OpenAI-like provider settings when switching modes

[roomote]

Description

This PR fixes an issue where OpenAI-like provider configurations (such as Jan.ai) were being reset when switching between different operation modes (Code, Orchestrator, etc.).

Problem

When users configured custom OpenAI-compatible providers and then switched between modes, their settings would be lost and they would have to reconfigure the provider each time.

Solution

The fix ensures that:

1. Current provider configurations are properly saved when switching to a mode that doesn't have a saved configuration
2. Custom OpenAI provider profiles are re-activated after being saved to ensure all settings persist correctly
3. The configuration persistence logic now works consistently for all provider types

Testing

• All existing tests pass ✅
• The fix preserves the expected behavior where configurations are saved as defaults for new modes
• Custom OpenAI provider settings now persist across mode switches

Related Issue

Fixes #8583

---

Important

Fixes provider settings reset issue in ClineProvider.ts by ensuring configurations are saved and reloaded correctly when switching modes.

• Behavior:
  • Fixes issue where OpenAI-like provider settings were reset when switching modes in ClineProvider.ts.
  • Ensures current provider configurations are saved as defaults for new modes if no saved config exists.
  • Re-activates custom OpenAI provider profiles to ensure settings persist across mode switches.
• Functions:
  • Updates handleModeSwitch() to save current config as default and re-activate profiles if needed.
  • Modifies activateProviderProfile() to ensure settings are properly loaded for OpenAI providers.

^{This description was created by for 0e3fe0e. You can customize this summary. It will automatically update as commits are pushed.}

[roomote]

Reviewing my own code again. At least I'm consistent in my inconsistencies.

[roomote]

Minor: Consider adding error handling around the activateProviderProfile call. If activation fails, the mode switch will still complete but the provider settings might not be fully loaded.

Suggested change

	await this.activateProviderProfile({ name: currentConfig.name })
	try {
	await this.activateProviderProfile({ name: currentConfig.name })
	} catch (error) {
	this.log(`Failed to re-activate OpenAI provider profile during mode switch: ${error instanceof Error ? error.message : String(error)}`)
	}

[roomote]

Nitpick: The comment mentions "custom OpenAI providers" but the check is for apiProvider === "openai". Consider clarifying that this applies to all OpenAI-compatible providers configured through the "openai" provider type, not just custom ones. This would make the intent clearer for future maintainers.