Polish Android daily keyboard comfort

[RioPlay]

Summary

• quiet the suggestion strip with stable, borderless slots and no empty-state filler
• guarantee accessible bottom-row target widths and unify the dynamic action-key shape
• improve hint hierarchy plus pressed, focused, selected, and stale-state handling
• record the bounded clean-room comfort contract and roadmap status

Verification

• Android tooling: 26/26
• JVM tests and lintDebug: pass
• focused API 35 emulator bundle: 58/58
• final empty, one-candidate, and three-candidate renders inspected

Emulator evidence does not establish physical-phone comfort or live assistive-technology acceptance.