Linkboard - Cross-Device P2P

[Large File Transfer] Added streaming chunked transfer for payloads over 8 MB — read from disk in 256 KB windows so videos/archives no longer sit in RAM. [Live Progress] Bottom-right overlay shows per-transfer file name, size, percent, and live throughput (e.g. 12.4 MB · 26% · 3.2 MB/s) with cancel. [Resend from History] Long-press any history entry → Resend re-broadcasts to every currently-online device. [Faster Reconnect] Per-device exponential backoff (3s → 6 → 12 → 24 → 48 → 60s cap) replaces the fixed 60s sweep. Peers coming online are picked up within a few seconds; app resume forces an immediate re-check. [Handshake Trust Gate] Unknown peer handshakes now pop a consent dialog (60s auto-deny) so random LAN neighbours can't add themselves to your device list. Already-paired peers reconnect silently. [Bluetooth Warning] Before initiating a BLE connection, verify local advertising is on — if not, offer one-tap Enable that starts the peripheral and waits for it to go on air. [Polish] Type-specific file icons (PDF / video / audio / archive / code / installer / …), pinch-zoom previews from history and pinned-item detail dialogs, and clearer error surfacing when file-picking fails. [Stability] Fixed a Windows path bug that hid received images, an iOS OOM on large image lists, and HEIC filenames from iOS clipboard that Windows couldn't open.