fix(proxy): reduce unnecessary Copilot premium interaction consumption

- Fix request classification: treat messages containing tool_result as
  agent continuation instead of user-initiated, preventing false premium
  charges on every tool call
- Add subagent detection via __SUBAGENT_MARKER__ and metadata._agent_
  fallback, setting x-interaction-type=conversation-subagent
- Add deterministic x-interaction-id derived from session ID to group
  requests into a single billing interaction
- Add orphan tool_result sanitization to prevent upstream API errors
  that could cause retries and duplicate billing
- Reorder pipeline: classify (on original body) → sanitize → merge →
  warmup, ensuring classification sees raw tool_result semantics
- Enable warmup downgrade by default with gpt-5-mini model
- Enhance session ID extraction priority chain for Copilot cache keys
- Detect infinite whitespace bug in streaming tool call arguments

src-tauri/src/session_manager/providers/openclaw.rs

@@ -180,7 +180,10 @@ fn load_display_names(sessions_dir: &Path) -> HashMap<String, String> {
     map
 }
 
-fn parse_session(path: &Path, display_names: Option<&HashMap<String, String>>) -> Option<SessionMeta> {
+fn parse_session(
+    path: &Path,
+    display_names: Option<&HashMap<String, String>>,
+) -> Option<SessionMeta> {
     let (head, tail) = read_head_tail_lines(path, 10, 30).ok()?;
 
     let mut session_id: Option<String> = None;