Respect self-constraints on recursive extras (#9714)

## Summary

Sort of ridiculous, but today this passes, when it should fail:

```toml
[project]
name = "foo"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
requires-python = ">=3.13.0"
dependencies = []

[project.optional-dependencies]
async = [
    "foo[async]==0.2.0",
]
```

crates/uv-resolver/src/pubgrub/report.rs

@@ -1328,7 +1328,7 @@ impl std::fmt::Display for PubGrubHint {
             Self::DependsOnItself { package } => {
                 write!(
                     f,
-                    "{}{} The package `{}` depends on itself. This is likely a mistake. Consider removing the dependency.",
+                    "{}{} The package `{}` depends on itself at an incompatible version. This is likely a mistake. Consider removing the dependency.",
                     "hint".bold().cyan(),
                     ":".bold(),
                     package.cyan(),

crates/uv-resolver/src/resolver/mod.rs

@@ -1567,7 +1567,8 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             return requirements;
         }
 
-        // Check if there are recursive self inclusions and we need to go into the expensive branch.
+        // Check if there are recursive self inclusions; if so, we need to go into the expensive
+        // branch.
         if !requirements
             .iter()
             .any(|req| name == Some(&req.name) && !req.extras.is_empty())
@@ -1624,8 +1625,26 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             }
         }
 
+        // Retain any self-constraints for that extra, e.g., if `project[foo]` includes
+        // `project[bar]>1.0`, as a dependency, we need to propagate `project>1.0`, in addition to
+        // transitively expanding `project[bar]`.
+        let mut self_constraints = vec![];
+        for req in &requirements {
+            if name == Some(&req.name) && !req.source.is_empty() {
+                self_constraints.push(Requirement {
+                    name: req.name.clone(),
+                    extras: vec![],
+                    groups: req.groups.clone(),
+                    source: req.source.clone(),
+                    origin: req.origin.clone(),
+                    marker: req.marker,
+                });
+            }
+        }
+
         // Drop all the self-requirements now that we flattened them out.
-        requirements.retain(|req| name != Some(&req.name));
+        requirements.retain(|req| name != Some(&req.name) || req.extras.is_empty());
+        requirements.extend(self_constraints.into_iter().map(Cow::Owned));
 
         requirements
     }