fix: Use BTreeMap for bundled_deps in bun PackageIndex (#12266)

## Summary

- Switches `bundled_deps` in `PackageIndex` from `HashMap` to `BTreeMap`
for deterministic iteration order in `find_package()`

## Context

Follow-up to #12254. `find_package()` iterates `bundled_deps` and
returns the first match when a package isn't found via workspace-scoped
or top-level lookups. With `HashMap`, the per-process random seed
produces different iteration orders across `turbo` invocations, making
the result non-deterministic when multiple parents bundle the same
dependency name.

This is unlikely to trigger in practice (bundled deps are rare, and
having the same dep bundled by multiple parents is rarer), but it closes
the last remaining `HashMap` iteration on a hash-affecting code path
across all five lockfile implementations.

No performance impact — `bundled_deps` is almost always empty.

Closes #12252

Author: anthonyshew

crates/turborepo-lockfiles/src/bun/index.rs

@@ -1,6 +1,9 @@
 //! Package indexing for efficient lockfile lookups.
 
-use std::{collections::HashMap, sync::Arc};
+use std::{
+    collections::{BTreeMap, HashMap},
+    sync::Arc,
+};
 
 use super::{PackageEntry, types::PackageKey};
 
@@ -22,7 +25,8 @@ pub struct PackageIndex {
 
     /// Bundled dependency lookup
     /// Maps (parent_key, dep_name) -> lockfile key
-    bundled_deps: HashMap<(StringRef, StringRef), StringRef>,
+    /// BTreeMap for deterministic iteration in find_package().
+    bundled_deps: BTreeMap<(StringRef, StringRef), StringRef>,
 }
 
 impl PackageIndex {
@@ -31,7 +35,7 @@ impl PackageIndex {
         let mut by_key = HashMap::with_capacity(packages.len());
         let mut by_ident: HashMap<StringRef, Vec<StringRef>> = HashMap::new();
         let mut workspace_scoped = HashMap::new();
-        let mut bundled_deps = HashMap::new();
+        let mut bundled_deps = BTreeMap::new();
 
         // First pass: populate by_key and by_ident
         for (key, entry) in packages {

turbo.json

@@ -65,7 +65,8 @@
         "dist/**/*",
         ".next/**/*",
         "!.next/cache/**/*",
-        "!.next/dev/**/*"
+        "!.next/dev/**/*",
+        "!README.md"
       ],
       "dependsOn": ["^build"]
     },