BlindRSS v1.90.7

This release rolls up everything since v1.90.4 (the v1.90.4–v1.90.6 releases were pulled while a startup hang was investigated and fixed; v1.90.7 is the verified build). If you are updating from v1.90.3, all of the following is new:

Fixes

• Startup hang fixed. The app could go Not Responding shortly after launch and never recover (a deferred list-focus restore livelocked the event loop, starving all timers). Confirmed fixed by monitoring the shipped build: zero hung intervals where the previous build froze permanently.
• Startup lag fixed. The media-tools dependency scan (PATH/winget probing) no longer runs on the UI thread, and refresh cycles no longer re-parse the whole selected view (a content-keyed cache cuts repeat reload work from ~1.5s to ~45ms), so the background refresh can't make the app sluggish after launch.
• Playback speed changes are smooth. The audio output switched from DirectSound to WASAPI: speed changes no longer silence audio for up to 3 seconds. Speeds now step in clean 0.1 increments (1.1x, 1.2x, ...) instead of the old 0.12 grid (1.22x, 1.34x).
• Large-category and list navigation lag fixed. Expensive per-article work (media detection, description previews) moved off the UI thread; list rows append in small batches that let keyboard and screen-reader events through. Tree navigation, expand/collapse, and tabbing into the article list stay responsive while big views load.
• MacRumors full text no longer merges the next article. The extractor mistook MacRumors' "next article" teaser for a page-2 link; pagination detection is now strict and next-story links are ignored, with regression tests.
• Zero warnings in the test suite and the release build, including a real fix for a possible leaked ffmpeg process in the silence scanner.

Other

• docs: record the CallAfter self-requeue / timer starvation invariant