fix: resolve build errors and add comprehensive symlink tests

- Fixed E0425 error in src/skills/mod.rs by moving println! inside #[cfg(unix)] block where 'dest' variable is in scope
- Added missing 'identity' field to Config struct initializations in src/onboard/wizard.rs
- Fixed import paths for AIEOS identity functions in src/channels/mod.rs
- Added comprehensive symlink edge case tests in src/skills/symlink_tests.rs
- All 840 tests passing, 0 clippy warnings

Resolves issue #28: skills symlink functionality now works correctly on Unix platforms with proper error handling on non-Unix platforms

src/skills/mod.rs

@@ -631,3 +631,6 @@ description = "Bare minimum"
         assert_eq!(skills[0].name, "from-toml"); // TOML takes priority
     }
 }
+
+#[cfg(test)]
+mod symlink_tests;