feat(console): right-click "Copy value" for hashes/addresses under the cursor

Right-clicking the output now offers "Copy <value>" when a long alphanumeric token
(txid/blockhash/address, >=16 chars) is under the cursor — resolved via screenToTextPos.
Uses right-click so it never conflicts with the left-drag text selection.

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

src/ui/windows/console_tab.h

@@ -153,6 +153,7 @@ private:
     // Output filter
     char filter_text_[128] = {0};
     mutable int filter_match_count_ = 0;        // lines matching the text filter (for the toolbar)
+    std::string context_token_;                 // hash/address under the cursor at right-click
     mutable std::vector<int> visible_indices_;  // Cached for selection mapping
     
     // Wrapped line height caching (for variable-height text wrapping)