Respect requires-python when installing tools (#10401)

## Summary

This PR revives https://github.com/astral-sh/uv/pull/7827 to improve
tool resolutions such that, if the resolution fails, and the selected
interpreter doesn't match the required Python version from the solve, we
attempt to re-solve with a newly-discovered interpreter that _does_
match the required Python version.

For now, we attempt to choose a Python interpreter that's greater than
the inferred `requires-python`, but compatible with the same Python
minor. This helps avoid successive failures for cases like Posting,
where choosing Python 3.13 fails because it has a dependency that lacks
source distributions and doesn't publish any Python 3.13 wheels. We
should further improve the strategy to solve _that_ case too, but this
is at least the more conservative option...

In short, if you do `uv tool instal posting`, and we find Python 3.8 on
your machine, we'll detect that `requires-python: >=3.11`, then search
for the latest Python 3.11 interpreter and re-resolve.

Closes https://github.com/astral-sh/uv/issues/6381.
Closes https://github.com/astral-sh/uv/issues/10282.

## Test Plan

The following should succeed:

```
cargo run python uninstall --all
cargo run python install 3.8
cargo run tool install posting
```

In the logs, we see:

```
...
DEBUG No compatible version found for: posting
DEBUG Refining interpreter with: Python >=3.11, <3.12
DEBUG Searching for Python >=3.11, <3.12 in managed installations or search path
DEBUG Searching for managed installations at `/Users/crmarsh/.local/share/uv/python`
DEBUG Skipping incompatible managed installation `cpython-3.8.20-macos-aarch64-none`
DEBUG Found `cpython-3.13.1-macos-aarch64-none` at `/opt/homebrew/bin/python3` (search path)
DEBUG Skipping interpreter at `/opt/homebrew/opt/python@3.13/bin/python3.13` from search path: does not satisfy request `>=3.11, <3.12`
DEBUG Found `cpython-3.11.7-macos-aarch64-none` at `/opt/homebrew/bin/python3.11` (search path)
DEBUG Re-resolving with Python 3.11.7
DEBUG Using request timeout of 30s
DEBUG Solving with installed Python version: 3.11.7
DEBUG Solving with target Python version: >=3.11.7
DEBUG Adding direct dependency: posting*
DEBUG Searching for a compatible version of posting (*)
...
```

crates/uv-resolver/src/requires_python.rs

@@ -586,6 +586,17 @@ impl SimplifiedMarkerTree {
 pub struct LowerBound(Bound<Version>);
 
 impl LowerBound {
+    /// Initialize a [`LowerBound`] with the given bound.
+    ///
+    /// These bounds use release-only semantics when comparing versions.
+    pub fn new(bound: Bound<Version>) -> Self {
+        Self(match bound {
+            Bound::Included(version) => Bound::Included(version.only_release()),
+            Bound::Excluded(version) => Bound::Excluded(version.only_release()),
+            Bound::Unbounded => Bound::Unbounded,
+        })
+    }
+
     /// Return the [`LowerBound`] truncated to the major and minor version.
     fn major_minor(&self) -> Self {
         match &self.0 {
@@ -600,6 +611,15 @@ impl LowerBound {
             Bound::Unbounded => Self(Bound::Unbounded),
         }
     }
+
+    /// Returns `true` if the lower bound contains the given version.
+    pub fn contains(&self, version: &Version) -> bool {
+        match self.0 {
+            Bound::Included(ref bound) => bound <= version,
+            Bound::Excluded(ref bound) => bound < version,
+            Bound::Unbounded => true,
+        }
+    }
 }
 
 impl PartialOrd for LowerBound {
@@ -668,19 +688,6 @@ impl Default for LowerBound {
     }
 }
 
-impl LowerBound {
-    /// Initialize a [`LowerBound`] with the given bound.
-    ///
-    /// These bounds use release-only semantics when comparing versions.
-    pub fn new(bound: Bound<Version>) -> Self {
-        Self(match bound {
-            Bound::Included(version) => Bound::Included(version.only_release()),
-            Bound::Excluded(version) => Bound::Excluded(version.only_release()),
-            Bound::Unbounded => Bound::Unbounded,
-        })
-    }
-}
-
 impl Deref for LowerBound {
     type Target = Bound<Version>;
 
@@ -699,6 +706,17 @@ impl From<LowerBound> for Bound<Version> {
 pub struct UpperBound(Bound<Version>);
 
 impl UpperBound {
+    /// Initialize a [`UpperBound`] with the given bound.
+    ///
+    /// These bounds use release-only semantics when comparing versions.
+    pub fn new(bound: Bound<Version>) -> Self {
+        Self(match bound {
+            Bound::Included(version) => Bound::Included(version.only_release()),
+            Bound::Excluded(version) => Bound::Excluded(version.only_release()),
+            Bound::Unbounded => Bound::Unbounded,
+        })
+    }
+
     /// Return the [`UpperBound`] truncated to the major and minor version.
     fn major_minor(&self) -> Self {
         match &self.0 {
@@ -721,6 +739,15 @@ impl UpperBound {
             Bound::Unbounded => Self(Bound::Unbounded),
         }
     }
+
+    /// Returns `true` if the upper bound contains the given version.
+    pub fn contains(&self, version: &Version) -> bool {
+        match self.0 {
+            Bound::Included(ref bound) => bound >= version,
+            Bound::Excluded(ref bound) => bound > version,
+            Bound::Unbounded => true,
+        }
+    }
 }
 
 impl PartialOrd for UpperBound {
@@ -787,19 +814,6 @@ impl Default for UpperBound {
     }
 }
 
-impl UpperBound {
-    /// Initialize a [`UpperBound`] with the given bound.
-    ///
-    /// These bounds use release-only semantics when comparing versions.
-    pub fn new(bound: Bound<Version>) -> Self {
-        Self(match bound {
-            Bound::Included(version) => Bound::Included(version.only_release()),
-            Bound::Excluded(version) => Bound::Excluded(version.only_release()),
-            Bound::Unbounded => Bound::Unbounded,
-        })
-    }
-}
-
 impl Deref for UpperBound {
     type Target = Bound<Version>;