Add catalog-based multilingual notifications and diagnostics - #130

Notifications and diagnostics currently have fixed English text. This adds JSON language catalogs and a shared renderer so users can select another language in global-config-overlay:

:global ScriptLanguage "pt-BR";

/system/script/run global-config;

English remains the offline default. The catalogs cover the same 693 messages in 15 locales across feature scripts, modules (including Signalgrid), shared helpers, configuration loading, and historical change notifications. Locales: en, zh-CN, hi, es, ar, fr, bn, pt-BR, id, ur, ru, de, ja, pcm, and ar-EG. The 13 new locales are initial assisted translations; Nigerian Pidgin and Egyptian Arabic include manual drafting and dialect adaptation. Native speakers still need to review linguistic accuracy and terminology. Machine-readable values, API fields, native RouterOS error patterns, received commands, and migration code keep their original behavior.

• Download only applicable catalogs over HTTPS with certificate verification. Validate two- or three-letter locale codes (with optional region), schema, group keys, size, and placeholder compatibility; use compatible cache or English on failure. JSON text is never executed.

• Embed English defaults and local renderers for entry points that run before shared functions. Refresh catalogs after configuration reloads and script updates; support both RouterOS function types.

• Split six helpers into required global-functions.d/core-extra.rsc to keep the main script below Fetch's size budget. Initial setup includes it; older installations bootstrap it with validation before optional modules and reuse installed source offline.

• Add catalog generation/checks and isolated RouterOS fixtures. Python is development tooling only. Regenerate platform variants before distribution checksums. Configuration version 147 announces the feature.

Validation on RouterOS 7.24.5 stable, x86_64 VMware, routeros + wireless:

• 72 supported sources parsed during migration; the updated shared runtime also parsed. All 10,395 locale rendering checks and 10,395 native parameter checks passed across the 15 locales, with one locale per import.

• Behavioral fixtures cover notifications, email loop filtering, Netwatch, messaging authorization, firewall/bridge guards, utilities, standalone/deferred renderers, reload hooks, required-module bootstrap, and conditional change notices.

• Real verified HTTPS downloads matched published required-module bytes; health catalog downloads/rendering passed for all 14 non-English locales; offline caches, English reset, malformed JSON, stale schemas, and invalid locales passed. Temporary test state was removed.

• Twelve Python checks (including complete locale coverage and preserved interactive answer keys), generated-artifact checks, and whitespace checks passed. Upstream notification headers, including silent behavior, were preserved.

A single all-locale fixture is approximately 9 MB. The test VM restarted during that import, and the SSH session timed out. Per-locale bundles passed afterwards; --locale now supports smaller, repeatable imports. Production catalogs are below 17 KB.

Remaining integration coverage: RouterOS 7.22, WiFi-package variants, actual reboot persistence, hardware-specific paths, and real notification delivery. Fixtures do not upgrade packages, execute migration/chat commands, or change network settings. Full make was unavailable locally because GNU Make and HTML prerequisites are absent.

Usage, translation workflow, architecture, and validation details are in doc/languages.md.

Upstream synchronization: merged fork main at da3cbdb3 into the PR branch. This sync adds the Signalgrid note in contrib/telegram.md. All 12 catalog checks, generated-artifact checks, and whitespace checks passed after the merge. RouterOS tests were not repeated for this documentation-only upstream change.