SerialDripfeedFileTask

OpalTask: start a drip-feed run from a local file path.

Detailed description

Carries the serial.io permission scope with confirmation policy EveryCall. Same pacing overrides as serial.dripfeed-start, plus a path parameter pointing at a local file. On Android the path must resolve under the app's writable storage (QStandardPaths::AppDataLocation); paths outside the sandbox are rejected with a "copy the file into …" suggestion before any file I/O happens.

Files up to ~64 MiB are read into memory and handed to the manager via the same code path as the inline-payload variant. (True chunked streaming is a future extension that needs a matching extension to LineStreamRun's start() signature.)