fix(console): RPC command-reference modal audit fixes

- Clicking a command now actually closes the modal. It called
  ImGui::CloseCurrentPopup(), a no-op here (BeginOverlayDialog is Begin/
  BeginChild, not an ImGui popup), so the picker stayed open covering the input
  and the insert looked like it did nothing. Set show_commands_popup_=false.
- Search filter is now a member cleared when the modal opens, so it isn't stale
  on reopen after an outside-click / command-click dismiss (was reset only by
  the Close button).
- Esc dismisses the modal (this overlay has no built-in Esc handling), and the
  search box auto-focuses on open so the user can type immediately.
- Scale the 2-vs-3 column breakpoint (cmd-min-width) by dpiScale() — it was a
  logical-px threshold compared against a physical-px available width.
- Give each category's table a unique ImGui id (##cmdsN) instead of sharing
  "##cmds", and translate the 7 category names (Control/Network/... — command
  descriptions stay English) into all 8 languages; CJK subset rebuilt (+2).

(Investigated but rejected: the command-name blue was flagged as low-contrast
on light skins, but the modal card is a dark glass panel on every theme, so the
original color is correct — verified by rendering marble/light/color-pop-light.)

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

res/lang/de.json

@@ -185,6 +185,13 @@
     "console_auto_scroll": "Automatisch scrollen",
     "console_available_commands": "Verfügbare Befehle:",
     "console_capturing_output": "Erfasse Daemon-Ausgabe...",
+    "console_cat_blockchain": "Blockchain",
+    "console_cat_control": "Steuerung",
+    "console_cat_mining": "Mining",
+    "console_cat_network": "Netzwerk",
+    "console_cat_raw_transactions": "Rohtransaktionen",
+    "console_cat_utility": "Dienstprogramme",
+    "console_cat_wallet": "Wallet",
     "console_clear": "Leeren",
     "console_clear_console": "Konsole leeren",
     "console_cleared": "Konsole geleert",