fix(console): mop up audit minors — timestamp, filter count, new-line count

- D2: rpcTraceTimestamp used std::localtime (process-wide static tm) guarded by
  a private mutex that can't stop another thread's localtime from clobbering the
  shared buffer. Use localtime_r / localtime_s into a local tm (the codebase
  pattern) and drop the now-useless mutex. Runs on RPC worker threads.
- C1: the toolbar's "<N> matches" label read filter_match_count_ before
  renderOutput recomputed it, so it lagged one frame. Compute the visible/
  filtered set once at the top of render() (before the toolbar) and reuse it in
  renderOutput, so the count and the output share one consistent computation.
- C4: the "N new lines" indicator counted the raw drain count, inflating it with
  lines the active filter hides. Count only newly-added lines that pass the
  current filter, so the badge matches what the user sees on jumping to bottom.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/console_tab.h

@@ -175,6 +175,8 @@ private:
     std::string context_token_;                 // hash/address under the cursor at right-click
     mutable std::vector<int> visible_indices_;  // Cached for selection mapping
     bool folding_active_ = true;                // fold UI shown only in the unfiltered (foldable) view
+    bool has_text_filter_ = false;              // computed once per frame (before the toolbar draws it)
+    std::string filter_lower_;                  // lowercased filter needle for match highlighting
 
     // Wrap layout for the visible lines (segments + per-line heights + cumulative Y),
     // recomputed each frame by the pure BuildConsoleLayout (console_text_layout.h) and