Search and on-screen keyboard: fuzzy search across the library (titles, people, albums), grid OSK optimised for D-pad, phone-remote text input, voice out of scope

Epic: #113 · Milestone: MC7 — TV shell

Tasks

• OSK widget (grid layout with space/backspace/symbols, long-press for caps), T9-style alternative, focus-engine tested.
• Search index: prefix + fuzzy (acronym) match over the library DB (in-memory trie rebuilt on scan), results grouped by type, live results as you type (≤ 50 ms per keystroke).
• Phone remote text field injects into the OSK (#100).
• Search screen .stx with recent searches.

Acceptance

Scripted OSK test types "matrix" and lands on the movie; latency measured in QEMU and on the Pi.

Size: S · Depends on: #91, #102 · Blocks: —