JetBrains docs (verified via the 2025.3 announcement post): in plugin
model v2 (which IntelliJ Platform 2025.2+ requires for bundled-module
deps), `intellij.spellchecker` is a V2 module with its own classloader,
NOT a separately-installable plugin ID. The legacy
`<depends>com.intellij.spellchecker</depends>` syntax declares a
plugin-ID dep and fails verification:
Plugin zshrs depends on unknown plugin com.intellij.spellchecker
Correct syntax for v2 modules: a separate `<dependencies>` block with
`<module name="..."/>` nested inside:
<dependencies>
<module name="intellij.spellchecker"/>
</dependencies>
This commit replaces the legacy depends tag with the v2 dependencies
block. build.gradle.kts already had `bundledModule("intellij.spellchecker")`
for compile-time resolution; this fixes the runtime EP wiring.
Source: https://blog.jetbrains.com/platform/2025/11/intellij-platform-2025-3-what-plugin-developers-should-know/