Add Spanish translations

[vgmarimon]

When merged this pull request will:

• Complete the Spanish localization of ZEN, adding 725 entries across 33 components (Spanish goes from 12.86% to 100%, 832/832 keys)
• Fix STR_ZEN_Modules_ModuleSuicideBomber_AutoSeek_Tooltip, which had lost its \n and used terminology inconsistent with its sibling key
• Fix STR_ZEN_Damage_HitTail, left untranslated while its sibling hit points were translated
• Trim trailing whitespace in the value of STR_ZEN_Damage_HitPitotTube

The last substantial Spanish contribution was #614 back in 2021, so everything added since then had no Spanish at all — including zen_modules (355 keys, 43% of all text in the mod) which sat at 2.8%, and zen_editor which had none.

Notes on conventions followed

• <Spanish> is added as the last child of each <Key>, matching how Add French translations #807 added French.
• Music track titles are kept verbatim (A2 OA: Iron Mountain); only the generic suffix is localized (This Is War - Part 1 → Parte 1), same as the French entries do.
• Technical terms Spanish-speaking mission makers use untranslated are left as-is: unscheduled in the zen_attributes code-execution descriptions, and the acronyms EOD, ERA, NVG, JIP, CQB, LZ, RP, CAS.
• Terminology follows Arma 3's Spanish localization and the Spanish already in the repo: side → bando, curator → curador, waypoint → punto de destino, stance → postura, loadout → equipamiento, pylons → pilones.

Checks run

sqf_validator.py, config_style_checker.py, stringtable_validator.py and return_checker.py all pass. I also scripted a check over all 832 Spanish entries confirming every one preserves the \n sequences and the %1/%2 placeholders of its English source, that none is empty or has stray whitespace, and that no stringtable gained a BOM or a tab.

Disclosure

The translations were produced with AI assistance (Claude) and reviewed by me. They have not yet been proofread in-game, so wording in context — particularly short UI labels where the English is ambiguous — is the place worth a second look. Happy to adjust anything on request.