feat: OUI manufacturer name lookup for device messages

[dougborg]

Summary

Add human-readable manufacturer name lookup based on MAC OUI prefix. Companion apps can then display "Apple", "Flock Safety", "Motorola Solutions", etc. without shipping their own OUI database.

Inspired by ESP32DualBandWardriver's OUI-to-manufacturer tables.

Design

• Add optional manufacturer field to WiFiScan and BleScan device messages
• Lookup table in defaults.rs — compact &[(&[u8; 3], &str)] static array
• no_std compatible — static table, no allocation needed
• Binary search on sorted OUI prefixes for O(log n) lookup

Scope

• Start with surveillance-relevant OUIs (already have OUI prefixes in defaults.rs for matching)
• Add common consumer OUIs for context (Apple, Samsung, Google, Xiaomi, etc.)
• Keep bounded — top ~100 OUIs, not the full IEEE database (~30K entries)
• Companion apps can supplement with their own full OUI database if needed

Notes

• This is distinct from OUI-based matching (which triggers alerts) — this is purely informational display data
• Field should be present even for non-matching devices, so companion apps always have context

Relates To

• spec: NDJSON wire protocol v1 schema and v2 roadmap #9 — protocol v2 (new field addition)
• Extend NDJSON protocol with new message types #71 — companion app (primary consumer of this data)