#14934: fix: add mistral to MemorySearchSchema provider/fallback unions

## Summary - The Mistral embedding provider was added to the runtime code but the Zod config schema (`MemorySearchSchema`) was not updated - Setting `agents.defaults.memorySearch.provider: "mistral"` or `fallback: "mistral"` causes config validation to fail with `Invalid input` - This silently breaks cron job execution since the gateway cannot load the config ## Changes - Added `z.literal("mistral")` to the `provider` union in `MemorySearchSchema` - Added `z.literal("mistral")` to the `fallback` union in `MemorySearchSchema` ## Test plan - [ ] Set `agents.defaults.memorySearch.provider` to `"mistral"` in config - [ ] Verify `openclaw doctor` passes config validation - [ ] Verify cron jobs execute without config load errors 🤖 Generated with [Claude Code](https://claude.com/claude-code) <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates the agent runtime Zod config schema (`src/config/zod-schema.agent-runtime.ts`) to recognize the Mistral embedding provider in `MemorySearchSchema`. Concretely, it adds `"mistral"` to the allowed literal unions for both `memorySearch.provider` and `memorySearch.fallback`, aligning schema validation with the already-supported runtime provider so configs like `agents.defaults.memorySearch.provider: "mistral"` no longer fail validation (which previously prevented config load and could block cron job execution). <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - The change is a small, additive schema update (adding a single allowed literal value) in the same pattern as existing providers, with no behavioral logic changes and no new branching paths. - No files require special attention _{Last reviewed commit: 59f05ef} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->