[BUG] Plugin inner classes ($ entries) cannot be resolved by the plugin classloader

- Severity: Medium
- Location:
`shenyu-web/src/main/java/org/apache/shenyu/web/loader/PluginJarParser.java:66` (`!entryName.contains("$")`); `shenyu-web/src/main/java/org/apache/shenyu/web/loader/ShenyuPluginClassLoader.java:118-139` (`findClass`)
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Description:
`parseJar` excludes any entry containing `$` from `clazzMap` and stores it in `resourceMap`. `findClass` only consults `classCache` and `clazzMap`; it never reads `resourceMap`. So `Outer$Inner` is unfindable: `ability("Outer$Inner")` returns true → delegates to `getParent().loadClass(...)` → app classloader cannot see plugin classes → `ClassNotFoundException`.
-
Impact:
Any uploaded/ext plugin referencing a nested/inner class (Builder pattern, nested enums, synthetic accessors) throws `NoClassDefFoundError` on first use at runtime; the plugin effectively can't use inner classes.
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Suggested fix:
Put `$`-bearing `.class` entries into `clazzMap` too, or have `findClass` fall back to `resourceMap` for names containing `$`.
-
Confidence: Medium
- Related existing: none

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_Identified during the 2026-08-02 deep re-scan; full list in [`docs/scan2-2026-08-02/06-medium-tiers.md`](docs/scan2-2026-08-02/06-medium-tiers.md)._

Start with PluginJarParser.java:66 and ShenyuPluginClassLoader.java:118-139, then trace how plugin class entries move between clazzMap, resourceMap, and classCache. Verify the behavior with a plugin containing an Outer$Inner class. Done means the nested class resolves through the plugin classloader without delegating unsuccessfully to the application classloader.

Written by the indexing model from the issue text.