feat: hook ownership model with external manager detection

Implement two-mode hook ownership: GitButler-managed (installs hooks
directly) vs externally-managed (defers to prek/lefthook/husky).

- Add hook_manager.rs: detect external managers via config + binary gate
- Refactor managed_hooks.rs: ensure_managed_hooks() shared entry point
- Add pre-push guard hook (blocks pushing gitbutler/workspace)
- Add --no-hooks / --force-hooks escape hatches to setup/teardown
- Hook lifecycle: staleness detection, auto-update, config persistence
- Desktop app (integration.rs) uses same ensure_managed_hooks() path

Addresses #12748

refactor: extract but-hooks crate from gitbutler-repo

feat: add but hook CLI subcommands for hook manager integration

Expose GitButler workspace guard and cleanup as standalone CLI commands
that external hook managers can invoke from their configuration:

- but hook pre-commit: blocks git commit on gitbutler/workspace
- but hook post-checkout: info message when leaving workspace branch
- but hook pre-push: blocks git push on gitbutler/workspace
- but hook status: diagnostic view of hook ownership and integration state

Follows up on hook-ownership-core.

Author: Ismar Iljazovic

Cargo.lock

@@ -35,6 +35,7 @@ members = [
     # 👉mostly powered by legacy, but will help to transition to `but-db` backing.
     "crates/but-meta", # 📄An interface to support Git-entity metadata;
     # 👉lacks tests
+    "crates/but-hooks",           # 📄Git hook management: external manager detection and managed hook installation.
     "crates/but-hunk-assignment", # 📄Assign uncommitted changes to stacks/lanes.
     # 👉uses `but-ctx`.
     "crates/but-hunk-dependency", # 📄Assuming it works, it feels close to 'Exemplary',
@@ -157,6 +158,7 @@ but-worktrees = { path = "crates/but-worktrees" }
 but-db = { path = "crates/but-db" }
 but-path = { path = "crates/but-path" }
 but-graph = { path = "crates/but-graph" }
+but-hooks = { path = "crates/but-hooks" }
 but-meta = { path = "crates/but-meta" }
 but-rules = { path = "crates/but-rules" }
 but-action = { path = "crates/but-action" }
@@ -212,6 +214,7 @@ gitbutler-workspace = { path = "crates/gitbutler-workspace" }
 rusqlite = { version = "0.39.0", features = ["bundled"] }
 backoff = "0.4.0"
 bstr = "1.12.1"
+which = "8.0.0"
 # Add the `tracing` or `tracing-detail` features to see more of gitoxide in the logs. Useful to see which programs it invokes.
 # When adjusting this, update `gix-testtools` as well!
 gix = { version = "0.81.0", git = "https://github.com/GitoxideLabs/gitoxide", rev = "700ad9ea517d8b2f2a2f7948d9e0bd0df1962a56", default-features = false, features = [

Cargo.toml

@@ -139,7 +139,7 @@ gix = { workspace = true, features = ["worktree-mutation"] }
 open.workspace = true
 url = { version = "2.5", optional = true }
 uuid.workspace = true
-which = "8.0.0"
+which.workspace = true
 but-schemars.workspace = true
 
 [dev-dependencies]

crates/but-api/Cargo.toml

@@ -114,7 +114,10 @@ mod ext;
 pub use ext::ObjectStorageExt;
 
 mod repo_ext;
-pub use repo_ext::{RepositoryExt, update_head_reference};
+pub use repo_ext::{
+    GITBUTLER_COMMIT_AUTHOR_EMAIL, GITBUTLER_COMMIT_AUTHOR_NAME, RepositoryExt, commit_time,
+    committer_signature, update_head_reference,
+};
 
 /// Return `true` if `ref_name` looks like the standard GitButler workspace.
 ///

crates/but-core/src/lib.rs

@@ -466,12 +466,14 @@ impl RepositoryExt for gix::Repository {
     }
 }
 
-const GITBUTLER_COMMIT_AUTHOR_NAME: &str = "GitButler";
-const GITBUTLER_COMMIT_AUTHOR_EMAIL: &str = "gitbutler@gitbutler.com";
+/// The display name used for commits authored by GitButler itself.
+pub const GITBUTLER_COMMIT_AUTHOR_NAME: &str = "GitButler";
+/// The email address used for commits authored by GitButler itself.
+pub const GITBUTLER_COMMIT_AUTHOR_EMAIL: &str = "gitbutler@gitbutler.com";
 
 /// Provide a signature with the GitButler author, and the current time or the time overridden
 /// depending on the value for `purpose`.
-fn committer_signature() -> gix::actor::Signature {
+pub fn committer_signature() -> gix::actor::Signature {
     gix::actor::Signature {
         name: GITBUTLER_COMMIT_AUTHOR_NAME.into(),
         email: GITBUTLER_COMMIT_AUTHOR_EMAIL.into(),
@@ -481,7 +483,7 @@ fn committer_signature() -> gix::actor::Signature {
 
 /// Return the time of a commit as `now` unless the `overriding_variable_name` contains a parseable date,
 /// which is used instead.
-fn commit_time(overriding_variable_name: &str) -> gix::date::Time {
+pub fn commit_time(overriding_variable_name: &str) -> gix::date::Time {
     std::env::var(overriding_variable_name)
         .ok()
         .and_then(|time| gix::date::parse(&time, Some(std::time::SystemTime::now())).ok())

crates/but-core/src/repo_ext.rs

@@ -0,0 +1,25 @@
+[package]
+    authors.workspace     =true
+    edition.workspace     =true
+    name                  ="but-hooks"
+    publish               =false
+    rust-version.workspace=true
+    version               ="0.0.0"
+
+[lib]
+    doctest=false
+
+[dependencies]
+    but-core.workspace=true
+
+    anyhow.workspace =true
+    gix.workspace    =true
+    tracing.workspace=true
+    which.workspace  =true
+
+[dev-dependencies]
+    temp-env          ="0.3"
+    tempfile.workspace=true
+
+[lints]
+    workspace=true