[codex] Add display-safe chat text rendering

[n30nex]

Summary

• add a UI-layer display-safe text sanitizer for chat/notification rendering
• sanitize Messages rows, conversation header/bubbles/draft text, and lock-screen notification text before LVGL measures/renders it
• add native selftest vectors for ASCII, controls, malformed UTF-8, punctuation aliases, emoji aliases, caps, and null input
• add a native screenshot case for a long emoji draft in the compose pill
• mark the V0.9 emoji-polish roadmap slice as in progress

Local validation

• git diff --check
• pio run -e native
• .pio\\build\\native\\program.exe --selftest
• .pio\\build\\native\\program.exe --simtest
• .pio\\build\\native\\program.exe --shots .pio\\native-shots-display-safe
• visual spot-check: .pio\\native-shots-display-safe\\17b-convo-safe-draft.bmp rendered ETA 12 fire near waypoint, bring bat pack in the compose pill

GitHub Actions

• Firmware CI: pass
• Run: https://github.com/ItsLimitlezz/LimitlezzOS/actions/runs/27872850182
• Commit: 378bde99cf23ebd35e123d0d2759b945f91dca92
• Artifact: tdeck-firmware-378bde99cf23ebd35e123d0d2759b945f91dca92
• Manifest: budget_status=pass, firmware_bytes=1578352, static_ram_bytes=230196

COM8 hardware validation

• Port: COM8 only (USB Serial Device, VID_303A&PID_1001, status OK)
• Flash: direct PlatformIO esptool no-stub flash of the exact Actions artifact
• Device: ESP32-S3 rev v0.2, MAC cc:8d:a2:0d:14:28
• Flash result: bootloader, partitions, boot_app0, and firmware hashes verified
• Smoke command: python scripts\\tdeck_smoke.py --port COM8 --skip-upload --open-timeout 60 --boot-timeout 90 --timeout 45 --no-expect --commands id sys net rf stats wifi "companion test"
• Smoke result: PASS
• Observed identity: !a20d1428 "limitlessdeck" (LIMI)
• Observed system: battery 100% at 4.42V USB, RAM 42/151KB
• Observed RF: Meshtastic 100%, MeshCore off, RF diagnostics responsive
• Observed companion test: PASS (fw=2.7.15.567b8ea, min_app=30200)