feat: render map connections in CLI TUI

[chiimagnus]

Motivation

• Provide a clearer, connected map view in the CLI TUI by drawing the node links between rows.
• Allow connection lines to cross where necessary while keeping the existing map generation and node semantics unchanged.
• Improve map readability without touching map generation logic or RunState behavior.

Description

• Replace the previous per-row simple string rendering with a grid-based canvas layout that computes node positions and aligns rows centrally.
• Add a line-drawing routine (Bresenham-like) that draws connections between node positions using box-drawing characters (│, ─, ╲, ╱) and permits line crossings.
• Preserve existing node styling and row prefixes (start/boss/current) by rendering styled node labels via formatNode and composing them with the canvas output.
• No changes were made to map generation (MapGenerator) or RunState; only Sources/GameCLI/Screens/MapScreen.swift was modified.

Testing

• No automated tests were run for this change.
• swift test was not executed as part of this rollout.

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Codex Task