fix(joplin_desktop): drop --disable-dev-shm-usage, Joplin rejects unknown flags (#3113)

Joplin validates its argv against an allow-list (processStartFlags.ts) and
aborted with "Unknown flag: --disable-dev-shm-usage", so the app never opened.
Bump to 3.7.21.1 so Supervisor offers the rebuild, and record the trap in the
workflow skill.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.claude/skills/hassio-addon-workflow/references/traps.md

@@ -226,7 +226,7 @@ against an allow-list and aborts on anything else: `--disable-dev-shm-usage` pro
 (`packages/lib/utils/processStartFlags.ts`; it accepts `--no-sandbox`, `--ozone-platform=`,
 `--disable-gpu` and a few others). The build-time `grep` that "verified" the flag only proved
 the text was in the wrapper, not that the app tolerated it. Check the app's argument parser before
-passing a Chromium flag to anything that is not Chromium itself (joplin_desktop, PR #3112).
+passing a Chromium flag to anything that is not Chromium itself (joplin_desktop, PR #3112, fixed in the follow-up PR).
 
 ## CI and review bots
 

joplin_desktop/CHANGELOG.md

@@ -1,4 +1,7 @@
 
+## 3.7.21.1 (2026-10-11)
+- Fix Joplin not opening ("An error occurred: Unknown flag: --disable-dev-shm-usage"): Joplin only accepts its own list of command-line flags, so the extra Chromium flag added in 3.7.21 is removed
+
 ## 3.7.21 (2026-10-11)
 - Initial release: Joplin desktop streamed to the browser with Selkies, based on linuxserver/docker-joplin (amd64 only, as Joplin publishes no Linux arm64 build)
 - Shares the Selkies startup scripts with the webtop and claude_desktop add-ons (data location, GPU permissions, ingress, SSL)

joplin_desktop/config.yaml

@@ -103,5 +103,5 @@ schema:
 slug: joplin_desktop
 udev: true
 url: https://github.com/alexbelgium/hassio-addons/tree/master/joplin_desktop
-version: "3.7.21"
+version: "3.7.21.1"
 video: true