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/identity/aieos.rs

@@ -1056,11 +1056,7 @@ impl AieosEntity {
                     }
                 }
                 if let Some(slang) = style.slang_usage {
-                    let _ = writeln!(
-                        prompt,
-                        "- **Slang:** {}",
-                        if slang { "yes" } else { "no" }
-                    );
+                    let _ = writeln!(prompt, "- **Slang:** {}", if slang { "yes" } else { "no" });
                 }
                 if !style.style_descriptors.is_empty() {
                     let _ = writeln!(