Visor: make glyph selection a modal with Random action

[lannbot]

Summary

• Move glyph randomization into the picker as an always-active Random action; remove outer glyph dice, Clear glyph, and glyph-specific roll eligibility.
• Open the picker as a native modal dialog with outside-click/tap, Escape, and Close dismissal; preserve selection focus restoration and Save/Revert.
• Constrain the panel to the dynamic viewport with internally scrolling results.

Verification

• Passed Rust/Deno checks and tests, Wasm build, and composed site build.
• All 33 Chromium scenarios passed, including native modal state, keyboard focus containment, outside click/tap without background activation, Random/manual selection, and persistence.
• Verified a 390x400 viewport retains a 12px gutter with Random, search, and Close visible.

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