Fix search results Map View interactions

[ewlarson]

Summary

• clarify the current-page map notice and add a responsive info treatment
• keep result highlighting without scrolling the page on pin hover
• use governed BTAA blue tokens and result-list punctuation for numbered pins
• restore default overlapping-marker spiderfier behavior

Testing

• full frontend Vitest suite
• focused Map View and Search Page tests
• production frontend build
• ESLint and Prettier checks on changed files