chore(release): finalize 1.0.18 notes and public file inventory

Document the tool availability fallback, the mid-transfer download
failure handling, the managed tools status hint and the unified
auto-install error messages in the 1.0.18 changelog, move the release
date to 2026-08-14 and add the new src/tools.test.ts suite to the public
release file inventory.

CHANGELOG.md

@@ -1,7 +1,11 @@
 # Changelog
 
-## 1.0.18 - 2026-08-13
+## 1.0.18 - 2026-08-14
 
+- Keep downloads working through a runnable system-provided Streamlink or FFmpeg even when the managed tool installation cannot be repaired right away.
+- Fail managed tool downloads cleanly when the connection breaks mid-transfer instead of leaving the download start waiting indefinitely.
+- Show in Settings when downloads remain available through a system installation while a managed tool is missing or unverified.
+- Explain failed automatic tool installations consistently across single, live and merged downloads.
 - Keep update downloads, progress, errors and changelog controls contained and responsive throughout the complete update flow.
 - Preserve System Check results across language changes and keep repeated diagnostics in a clear terminal state.
 - Expand Live Debug Log and Runtime Metrics layouts, improve dark-theme controls and make navigation and settings labels easier to read.

scripts/public-release-files.json

@@ -151,6 +151,7 @@
     "src/renderer-vod-hover.ts",
     "src/renderer.ts",
     "src/styles.css",
+    "src/tools.test.ts",
     "src/tools.ts",
     "src/types.ts",
     "src/workspace.css",