feat(mining): migrate the Windows Defender antivirus-help dialog to reference design

Bring renderAntivirusHelpDialog onto the reference design and remove its hardcoded
English (the last Wave-1 modal):
- struct-form BeginOverlayDialog(OverlayDialogSpec{BlurFloat, cardWidth 560,
  idSuffix antivirus}) replacing the legacy positional overload
- the hardcoded "Windows Defender Blocked Miner" title and all 10 step/intro/bullet
  strings -> TR() (11 new av_* keys + reuse `close`; 8-lang translations, Windows
  env vars / xmrig.exe kept literal, menu names localized)
- 2 StyledButton -> TactileButton, drop the footer divider, dp-scale the button widths
- CJK subset rebuilt (glyphs 1741->1751; kept — new glyphs are used)

NOTE: this dialog is inside #ifdef _WIN32, so the Linux build compiles it out and
cannot verify it — needs a Windows build to compile-check. The edits mirror the
already-verified daemon-update-prompt / migrate-to-seed struct-overlay pattern and
leave the ShellExecuteA call untouched. i18n.cpp + the daemon prompt (cross-platform)
build + ctest + hygiene clean on Linux.

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

src/util/i18n.cpp

@@ -1940,6 +1940,18 @@ void I18n::loadBuiltinEnglish()
         strings_["explorer_txid"] = "TxID:";
         strings_["explorer_prev_block"] = "Previous block";
         strings_["explorer_next_block"] = "Next block";
+        // --- Antivirus (Windows Defender) help dialog (Windows-only) ---
+        strings_["av_title"] = "Windows Defender Blocked Miner";
+        strings_["av_intro"] = "Mining software is often flagged as potentially unwanted. Follow these steps to enable pool mining:";
+        strings_["av_step1"] = "Step 1: Add Exclusion";
+        strings_["av_step1_b1"] = "Open Windows Security > Virus & threat protection";
+        strings_["av_step1_b2"] = "Click Manage settings > Exclusions > Add or remove";
+        strings_["av_step1_b3"] = "Add folder: %APPDATA%\\ObsidianDragon\\";
+        strings_["av_step2"] = "Step 2: Restore from Quarantine (if needed)";
+        strings_["av_step2_b1"] = "Windows Security > Protection history";
+        strings_["av_step2_b2"] = "Find xmrig.exe and click Restore";
+        strings_["av_step3"] = "Step 3: Restart wallet and try again";
+        strings_["av_open_security"] = "Open Windows Security";
         strings_["explorer_invalid_query"] = "Enter a block height or 64-character hash";
         strings_["explorer_invalid_response"] = "Invalid response from daemon";
         strings_["explorer_hash_not_found"] = "No block or transaction found for this hash";