🚀 Release v1.4.0 — Reset Config, Smart Diff Truncation & README updates (#43)

* ```
feat: ✨ Add LiteLLM reset configuration command and improve config handling

This commit introduces a new command to reset all LiteLLM configurations, providing users with a "nuke" option for their settings. It also refactors configuration handling to use a dedicated `apiKeySecretRef` for better management of API keys stored in VS Code's SecretStorage.

- **✨ Features**
  - Add `litellm-connector.reset` command to clear all LiteLLM configuration settings.
  - Introduce `apiKeySecretRef` setting to manage which API key entry in SecretStorage is used, defaulting to "default".
  - Update `ConfigManager` to store and retrieve API keys using the `apiKeySecretRef` for namespacing.
  - Modify `discoverModels` to trigger the classic configuration flow when no base URL is set and `silent` is false.

- **🐛 Fixes**
  - Remove deprecated `convertProviderConfiguration` and migration logic, as configuration is now handled directly by VS Code's provider API.
  - Ensure `cleanupAllConfiguration` correctly clears the canonical API key secret entry.

- **🧹 Chores**
  - Update `package.json` with the latest version and VS Code engine requirements.
  - Remove unused migration code and related tests.
  - Refactor provider base class to avoid passing `configuration` in `provideLanguageModelChatResponse` and `provideLanguageModelChat`.
  - Clean up unnecessary imports and types.
```

* ci: Update CI workflow branches

- **✨ Features**
  - Add `dev` and `dev/**` branches to trigger CI on new development branches.
  - Include `bugfix/**`, `enhance/**`, and `feat/**` branches for feature development workflows.
- **🧹 Chores**
  - Remove `geth-dev` from the default push triggers, it's now explicitly included.
  - Add `geth-dev` and `dev` to pull request triggers for broader testing.

* chore: Remove unused import in liteLLMProviderBase.test.ts

- Remove the `ConfigManager` import from `liteLLMProviderBase.test.ts` as it is no longer used in the file.

* feat: 💡 Use model capabilities for diff truncation

- **✨ Features**
  - Dynamically determine `maxTokens` for diff truncation based on the selected model's capabilities. This ensures more accurate context window management for various models.
  - Pass the `modelId` to `GitUtils.checkDiffSize` for more informative logging when diff truncation occurs. This helps in debugging and understanding which models are experiencing truncation.

* chore: Skip LiteLLM error handling tests in CI

- **🧹 Chores**
  - Skip the LiteLLM error handling integration tests when running in a CI environment. This prevents test failures due to the unavailability of a real LiteLLM instance and ensures more reliable test execution in CI pipelines.

* feat: Add troubleshooting guide to READMEs 📄

- **✨ Documentation**
  - Added a new "Troubleshooting" section to both `README.md` and `README.marketplace.md`.
  - This section provides users with clear steps to resolve common connection and on-boarding issues, including manual configuration, connection checks, and resetting the configuration.
  - Updated the version in `package.json` to reflect the changes.

* build: 🚀 Bump version to v1.4.0