perf(tui): coalesce rapid input redraws

[Andiveli]

Summary

Coalesce rapid input redraw requests behind a 12 ms deadline while preserving synchronized media-animation and stale-placement cleanup transactions.

Why

Related to #332 as an independent performance follow-up. This branch is based directly on current main, does not depend on the guild-icon feature chain, and changes no guild-icon files.

How

Keep the earliest pending redraw deadline, shorten a background deadline when input arrives, and consume media-animation requests in the redraw plan. The change is limited to the redraw scheduler and runtime integration.

Testing

• cargo fmt --all --check
• git diff --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-features (1,743 library tests passed, 1 binary test passed, 1 ignored)
• Manual test in a real terminal (responsiveness check remains for maintainer/CI environment)

Chain context

Guild icon chain: #333 -> compact -> media -> render
Independent: 📍 redraw coalescing -> main

Start: current main. End: rapid input no longer replaces the existing redraw deadline, while media cleanup remains synchronized. Follow-up: none required for #332. Out of scope: guild icon state, media, and rendering.

Screenshots or recordings

Not required; this is a timing/behavior optimization.

Checklist

• One logical change per PR.
• Link a related issue.
• No tokens, passwords, MFA codes, or raw auth bodies in code, tests, or logs.
• Change does not add self-bot automation, mass actions, or scraping.
• Updated README.md, if behavior or workflows changed (not required for this internal timing optimization).