#22069: fix(agents): add provider-specific hints for local model auth errors

When Ollama, vLLM, or LM Studio users configure a local model as their primary but forget to set an API key, they get a confusing error pointing to auth-store paths and `openclaw agents add` -- none of which applies to local providers. These providers just need any dummy value as a key to register (e.g. `OLLAMA_API_KEY="ollama-local"`), but the current error doesn't mention that. **Changes:** - `model-auth.ts`: detect known local providers (`ollama`, `vllm`, `lmstudio`) in the `resolveApiKeyForProvider` error path and show provider-specific hints with the right env var name and docs link - 3 new tests confirming ollama/vllm get specific hints while other providers still get the generic message **Before:** ``` No API key found for provider "ollama". Auth store: /path/to/auth-profiles.json (agentDir: ...). Configure auth for this agent (openclaw agents add <id>) or copy auth-profiles.json from the main agentDir. ``` **After:** ``` No API key found for provider "ollama". Ollama needs any value as API key to register as a provider. Set OLLAMA_API_KEY="ollama-local" or run "openclaw configure". Docs: https://docs.openclaw.ai/providers/ollama ``` Addresses the confusion in #22055, #4544, #1695. Complementary to #20872 (auto-discovery without key). <!-- greptile_comment --> <h3>Greptile Summary</h3> Improves error messages for local model providers (Ollama, vLLM, LM Studio) by adding provider-specific hints that explain users need to set a dummy API key value. Replaces generic auth-store error with targeted guidance including env var names and docs links. **Key changes:** - Added `localProviderHints` map in `resolveApiKeyForProvider` error path with custom messages for ollama/vllm/lmstudio - Created 3 new tests to verify specific hints appear for local providers vs generic message for cloud providers **Issues found:** - Test file lacks environment variable isolation - tests will fail if `OLLAMA_API_KEY`, `VLLM_API_KEY`, or `ANTHROPIC_API_KEY` happen to be set in the environment - LM Studio hint references `LMSTUDIO_API_KEY` env var, but this variable is not registered in the `envMap` (unlike ollama/vllm), so the suggested fix won't actually work <h3>Confidence Score: 2/5</h3> - PR has critical issues: tests lack env isolation and will fail unpredictably, plus LM Studio hint suggests non-functional fix - The core feature (provider-specific hints) is sound, but implementation has two logical errors: (1) tests don't isolate environment variables and will fail if certain env vars are set, following a pattern established elsewhere in the codebase that should have been followed; (2) the LM Studio hint tells users to set an env var that isn't actually supported in the code - Both files need attention - test file needs env isolation pattern applied to all 3 tests, and model-auth.ts needs LM Studio env var either added to envMap or hint message corrected _{Last reviewed commit: f43a7e0} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->