Update servers/slapi, tests, and tools crates (final batch) to use new mononoke justknob crate

Summary:
Mechanical step 10/10 of the BUCK dep swap from `//common/rust/shed/justknobs_stub:justknobs` to `//eden/mononoke/common/rust/justknobs_ext:justknobs`. See D106467432 for the motivation and the new crate.

After this diff, no crate under `fbcode/eden/mononoke/` depends on `//common/rust/shed/justknobs_stub:justknobs` directly. Every Mononoke caller now goes through `//eden/mononoke/common/rust/justknobs_ext:justknobs`, which enforces the Mononoke style rule that a missing or misspelled JustKnob panics at the call site instead of being silently masked by `unwrap_or(default)`.

**I confirmed that no other crates under `eden/mononoke` (besides the new `justknobs_ext`) depend directly on the `justknobs_stub` crate :

```
╰─>$ buck2 cquery 'kind("rust*", rdeps(fbcode//eden/mononoke/..., fbcode//common/rust/shed/justknobs_stub:, 1))' > /tmp/justknobs_stub_deps_mononoke.out
Skipped 101 incompatible targets:
  fbcode//eden/mononoke/clients/facebook/git_pushrebase:_git_universal_pushrebase_macos_arm64 (cfg:dev-linux-x86_64-fbcode-platform010-clang19-asan-ubsan-dev#5f46caaa1d33a3cc)
  fbcode//eden/mononoke/clients/facebook/git_pushrebase:_git_universal_pushrebase_macos_x86_64 (cfg:dev-linux-x86_64-fbcode-platform010-clang19-asan-ubsan-dev#5f46caaa1d33a3cc)
  fbcode//eden/mononoke/clients/facebook/git_pushrebase:git_universal_pushrebase (cfg:dev-linux-x86_64-fbcode-platform010-clang19-asan-ubsan-dev#5f46caaa1d33a3cc)
  ...
  fbcode//eden/mononoke/scs/if:source_control-py3-default-types__source_control/types.cpp (cfg:dev-linux-x86_64-fbcode-platform010-clang19-asan-ubsan-dev#d7f75479a3c4990a)
  fbcode//eden/mononoke/scs/if:source_control-py3-default-types__source_control/types_empty.cpp (cfg:dev-linux-x86_64-fbcode-platform010-clang19-asan-ubsan-dev#d7f75479a3c4990a)
  fbcode//eden/mononoke/scs/if:source_control-py3-default-types__source_control/types_fields.cpp (cfg:dev-linux-x86_64-fbcode-platform010-clang19-asan-ubsan-dev#d7f75479a3c4990a)
Buck UI: https://www.internalfb.com/buck2/1dc29406-336b-4608-a280-b6927dd85b18
Network: Up: 0B  Down: 0B
Command: cquery.
Time elapsed: 8.4s
[2026-05-27T11:41:08.160+01:00] Network: Up: 0B  Down: 0B
┬─[gustavoavena@devvm34754:/d/r/f/fbcode]─[10:41:08]  (954d0c1b1b)
╰─>$ cat /tmp/justknobs_stub_deps_mononoke.out | cut -d' ' -f1 | sort | uniq
fbcode//common/rust/shed/justknobs_stub:justknobs
fbcode//datainfra/privacy/policy_zones_metadata/fetch_policy_zones_label:fetch_policy_zones_label
fbcode//eden/mononoke/common/rust/justknobs_ext:justknobs
fbcode//eden/mononoke/common/rust/justknobs_ext:justknobs-unittest
```

Reviewed By: YousefSalama

Differential Revision: D106489346

fbshipit-source-id: d60926cfc9c12f0ed68fe8817ef1be862abc300a

Author: gustavoavena

eden/mononoke/tests/utils/BUCK

@@ -23,8 +23,8 @@ rust_library(
         "fbsource//third-party/rust:rand",
         "fbsource//third-party/rust:rand_distr",
         "//common/rust/shed/facet:facet",
-        "//common/rust/shed/justknobs_stub:justknobs",
         "//eden/mononoke/blobstore:blobstore",
+        "//eden/mononoke/common/rust/justknobs_ext:justknobs",
         "//eden/mononoke/derived_data:fsnodes",
         "//eden/mononoke/derived_data/content_manifest_derivation:content_manifest_derivation",
         "//eden/mononoke/features/changesets_creation:changesets_creation",

eden/mononoke/tests/utils/Cargo.toml

@@ -24,7 +24,7 @@ facet = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust
 filestore = { version = "0.1.0", path = "../../repo_attributes/filestore" }
 fsnodes = { version = "0.1.0", path = "../../derived_data/fsnodes" }
 futures = { version = "0.3.31", features = ["async-await", "compat"] }
-justknobs = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
+justknobs = { version = "0.1.0", path = "../../common/rust/justknobs_ext" }
 manifest = { version = "0.1.0", path = "../../manifest" }
 maplit = "1.0"
 mercurial_types = { version = "0.1.0", path = "../../mercurial/types" }

eden/mononoke/tests/utils/src/lib.rs

@@ -159,7 +159,7 @@ pub async fn list_working_copy_with_types(
         "scm/mononoke:derived_data_use_content_manifests",
         None,
         Some(repo.repo_identity().name()),
-    )? {
+    ) {
         let root = repo
             .repo_derived_data()
             .derive::<RootContentManifestId>(ctx, cs_id, DerivationPriority::LOW)

eden/mononoke/tools/admin/BUCK

@@ -61,7 +61,6 @@ rust_binary(
         "//common/rust/shed/facet:facet",
         "//common/rust/shed/fbinit:fbinit",
         "//common/rust/shed/futures_stats:futures_stats",
-        "//common/rust/shed/justknobs_stub:justknobs",
         "//common/rust/shed/sorted_vector_map:sorted_vector_map",
         "//eden/mononoke/blobrepo:blobrepo_hg",
         "//eden/mononoke/blobrepo_utils:blobrepo_utils",
@@ -79,6 +78,7 @@ rust_binary(
         "//eden/mononoke/common/metadata:metadata",
         "//eden/mononoke/common/mononoke_macros:mononoke_macros",
         "//eden/mononoke/common/permission_checker:permission_checker",
+        "//eden/mononoke/common/rust/justknobs_ext:justknobs",
         "//eden/mononoke/common/rust/sql_ext:sql_ext",
         "//eden/mononoke/common/scuba_ext:scuba_ext",
         "//eden/mononoke/common/time_measuring:time_measuring",

eden/mononoke/tools/admin/Cargo.toml

@@ -77,7 +77,7 @@ gix-hash = { version = "0.25.0", features = ["sha1"] }
 gix-object = "0.60.0"
 history_manifest = { version = "0.1.0", path = "../../derived_data/history_manifest" }
 itertools = "0.14.0"
-justknobs = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
+justknobs = { version = "0.1.0", path = "../../common/rust/justknobs_ext" }
 live_commit_sync_config = { version = "0.1.0", path = "../../features/commit_rewriting/live_commit_sync_config" }
 manifest = { version = "0.1.0", path = "../../manifest" }
 maplit = "1.0"

eden/mononoke/tools/admin/src/commands/fetch.rs

@@ -207,7 +207,7 @@ async fn display_fsnode(
         "scm/mononoke:derived_data_use_content_manifests",
         None,
         Some(repo.repo_identity().name()),
-    )?;
+    );
 
     let root_manifest_id: compat::ContentManifestId = if use_content_manifests {
         repo.repo_derived_data()

eden/mononoke/tools/admin/src/commands/megarepo/delete_no_longer_bound_files_from_large_repo.rs

@@ -89,7 +89,7 @@ pub async fn run(
         "scm/mononoke:derived_data_use_content_manifests",
         None,
         Some(large_repo.repo_identity().name()),
-    )?;
+    );
 
     let root: compat::ContentManifestId = if use_content_manifests {
         large_repo

eden/mononoke/tools/admin/src/commands/redaction/create_key_list.rs

@@ -184,7 +184,7 @@ async fn content_keys_for_paths(
         "scm/mononoke:derived_data_use_content_manifests",
         None,
         Some(repo.repo_identity.name()),
-    )?;
+    );
 
     let root_manifest_id: compat::ContentManifestId = if use_content_manifests {
         repo.repo_derived_data()

eden/mononoke/tools/admin/src/commands/redaction/list.rs

@@ -56,7 +56,7 @@ pub(super) async fn paths_for_content_keys(
         "scm/mononoke:derived_data_use_content_manifests",
         None,
         Some(repo.repo_identity().name()),
-    )?;
+    );
 
     let root: compat::ContentManifestId = if use_content_manifests {
         repo.repo_derived_data()