Merge upstream/main: Street View rework meets i18n

Upstream's Street View rework (second imagery provider, one source at a
time, OPEN STREET VIEW button, key-alternative guidance) rewrote exactly
the street-level regions this branch localizes.

Resolved as upstream logic + re-applied localization:

- keySetupCore: new unlock copy kept as msg() data; added
  keySetupAlternativeKeyNames() returning machine values (registry key
  names) so key-setup core stays English while presentation localizes.
- New src/ui/keyGuidance.js: localized key-guidance composer shared by
  layerPanel and streetLevelPresentation (requirement sentence plus the
  "or light X to use your Y key" alternatives tail, placeholders only).
- streetLevelPresentation: keyGuidance()/presentNearest()/presentMeta
  relocalized (t/tn + formatNumber instead of toLocaleString);
  renderModes and month-precision dates kept from upstream.
- layer-panels.html: upstream row ids, sl-meta-row and the new button
  kept, data-i18n hooks re-applied (incl. OPEN STREET VIEW fallback).
- es/ru catalogs: 13 new keys, stale unlock key replaced in place.

npm run i18n: complete for es and ru. npm test: 6345/6347; the one
failure (devFreshDotenv provenance) also fails on plain upstream/main
and on the pre-merge tip here - this machine leaks OPENAI_API_KEY into
spawned children with a replaced env, so it is environmental.

package.json

@@ -266,6 +266,7 @@
     "./layers/street-level": "./src/layers/streetLevel/index.js",
     "./layers/street-level/mapillary": "./src/layers/streetLevel/providers/mapillary/index.js",
     "./layers/street-level/mapillary/source": "./src/layers/streetLevel/providers/mapillary/source.js",
+    "./layers/street-level/google": "./src/layers/streetLevel/providers/google/index.js",
     "./tools": "./src/tools/index.js",
     "./tools/mcp": "./src/tools/mcp/index.js",
     "./tools/panel": "./src/tools/panel.js",