Mapbox and MapLibre bundle deduplication

[askmy-stack]

Background

Identified during OSS audit v2 of meridian.

Problem Statement

Both map libs ship.

Proposed Solution

Dynamic import Mapbox when token set.

Acceptance Criteria

• Implementation complete
• Tests pass
• Documented in README or docs/

Files / Modules Affected

frontend/src/components/map/

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Suggested labels: priority:medium, difficulty:intermediate, category:performance
Milestone: v2.0-features
OSS Audit: Master Backlog v2