#22419: Add filterReasoningContent config option for Xiaomi Mimo v2 flash

## Problem Xiaomi Mimo v2 flash model returns an annoying `reasoning_content` field in responses when in thinking mode: ```json "reasoning_content": "Okay, the user just asked me to introduce myself. That is a pretty straightforward request..." ``` This content appears unnatural and clutters responses. ## Solution This PR adds a new config option `filterReasoningContent` that strips `reasoning_content` from model responses when enabled. ### Usage Add to your `~/.openclaw/openclaw.json`: ```json { "agents": { "defaults": { "filterReasoningContent": true } } } ``` ### Changes 1. **`src/config/types.agent-defaults.ts`** - Added `filterReasoningContent?: boolean` to `AgentDefaultsConfig` 2. **`src/agents/pi-embedded-utils.ts`** - Added `stripReasoningContent()` function and updated `extractAssistantText()` 3. **`src/agents/pi-embedded-subscribe.handlers.messages.ts`** - Wired up config option 4. **`src/agents/tools/sessions-helpers.ts`** - Updated helper to support filtering The default is `false` to maintain backward compatibility. ## Testing Tested locally with the Xiaomi Mimo v2 flash model. When `filterReasoningContent: true`, the reasoning content is properly filtered from responses. <!-- greptile_comment --> <h3>Greptile Summary</h3> Added `filterReasoningContent` config option to strip `reasoning_content` fields from Xiaomi Mimo v2 flash model responses **Key changes:** - Added boolean config field `filterReasoningContent` to `AgentDefaultsConfig` (defaults to `false`) - Implemented `stripReasoningContent()` function using regex pattern to remove JSON `reasoning_content` fields - Wired up filtering in `extractAssistantText()` functions across message handlers and session helpers - Filtering applies during text sanitization pipeline alongside existing filters for thinking tags and tool calls **Issue found:** - Regex pattern for stripping `reasoning_content` uses `[^"']*` which won't handle escaped quotes correctly - will fail if reasoning content contains `\"escaped\"` quotes within the string value <h3>Confidence Score: 3/5</h3> - Safe to merge with one logical issue that may cause problems if reasoning content contains escaped quotes - Implementation is straightforward and maintains backward compatibility with default `false`. However, the regex pattern has a clear bug that will fail to correctly strip `reasoning_content` if the value contains escaped quotes. Whether this is critical depends on whether Xiaomi actually returns such content - if reasoning text is always simple prose without quotes, it may work fine in practice. - Pay attention to `src/agents/pi-embedded-utils.ts` line 223 - the regex pattern needs review _{Last reviewed commit: 2ffd5a4} <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} <!-- /greptile_comment -->