feat(console): persist accent toggle + add monochrome-text toggle

Persist the two console output display preferences and add a second toolbar
toggle for monochrome text.

- Persistence: new Settings fields console_line_accents / console_text_color
  (both default true, matching the ConsoleTab statics so an upgrade re-save
  can't flip visible behavior). Restored into the statics at startup in the App
  constructor, and saved from a diff-and-save after the console renders (only
  when a value actually changed — save() is disk I/O). The startup restore also
  fixes a pre-existing bug: scanline was only synced from settings when the
  Settings page or first-run wizard ran, so an existing wallet ignored a saved
  scanline preference on launch.
- Monochrome text: a new toolbar toggle (FORMAT_COLOR_TEXT, dimmed when off)
  next to the accent toggle. channelTextColor() early-returns the neutral
  COLOR_RESULT for every channel (and JSON syntax role) when off, leaving the
  left accent bars independent. COLOR_RESULT is contrast-floored per theme, so
  text stays readable on light and dark terminals.

Adds console_toggle_text_color to the English source + all 8 translations.
Verified: both toggles independent, persistence round-trips across restart,
monochrome readable on light + dark skins.

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

src/config/settings.h

@@ -189,6 +189,13 @@ public:
     bool getScanlineEnabled() const { return scanline_enabled_; }
     void setScanlineEnabled(bool v) { scanline_enabled_ = v; }
 
+    // Console output appearance: per-line left color accent bars, and per-channel text coloring.
+    // (Defaults match the ConsoleTab statics so an upgrade re-save doesn't flip visible behavior.)
+    bool getConsoleLineAccents() const { return console_line_accents_; }
+    void setConsoleLineAccents(bool v) { console_line_accents_ = v; }
+    bool getConsoleTextColor() const { return console_text_color_; }
+    void setConsoleTextColor(bool v) { console_text_color_ = v; }
+
     // Hidden addresses (addresses hidden from the UI by the user)
     const std::set<std::string>& getHiddenAddresses() const { return hidden_addresses_; }
     bool isAddressHidden(const std::string& addr) const { return hidden_addresses_.count(addr) > 0; }
@@ -482,6 +489,8 @@ private:
     std::string balance_layout_ = "classic";
     int portfolio_style_ = 0;   // Market portfolio row style (0 single / 1 two-line / 2 hero)
     bool scanline_enabled_ = true;
+    bool console_line_accents_ = true;   // left color accent bars in console output
+    bool console_text_color_ = true;     // per-channel text coloring in console output
     std::set<std::string> hidden_addresses_;
     std::set<std::string> favorite_addresses_;
     std::map<std::string, AddressMeta> address_meta_;