refactor(settings): resolve feature flags

lib/crates/fabro-config/src/lib.rs

@@ -15,9 +15,9 @@ pub use config::ConfigLayer;
 pub use fabro_util::path::expand_tilde;
 pub use home::Home;
 pub use resolve::{
-    ResolveError, resolve_cli, resolve_cli_from_file, resolve_project, resolve_project_from_file,
-    resolve_run, resolve_run_from_file, resolve_server, resolve_server_from_file, resolve_workflow,
-    resolve_workflow_from_file,
+    ResolveError, resolve_cli, resolve_cli_from_file, resolve_features, resolve_features_from_file,
+    resolve_project, resolve_project_from_file, resolve_run, resolve_run_from_file, resolve_server,
+    resolve_server_from_file, resolve_workflow, resolve_workflow_from_file,
 };
 pub use storage::{RunScratch, ServerState, Storage};
 

lib/crates/fabro-config/src/resolve/features.rs

@@ -0,0 +1,12 @@
+use fabro_types::settings::features::{FeaturesLayer, FeaturesSettings};
+
+use super::ResolveError;
+
+pub fn resolve_features(
+    layer: &FeaturesLayer,
+    _errors: &mut Vec<ResolveError>,
+) -> FeaturesSettings {
+    FeaturesSettings {
+        session_sandboxes: layer.session_sandboxes.unwrap_or(false),
+    }
+}

lib/crates/fabro-config/src/resolve/mod.rs

@@ -1,16 +1,19 @@
 mod cli;
 mod error;
+mod features;
 mod project;
 mod run;
 mod server;
 mod workflow;
 
 use fabro_types::settings::{
-    CliSettings, ProjectSettings, RunSettings, ServerSettings, SettingsFile, WorkflowSettings,
+    CliSettings, FeaturesSettings, ProjectSettings, RunSettings, ServerSettings, SettingsFile,
+    WorkflowSettings,
 };
 
 pub use cli::resolve_cli;
 pub use error::ResolveError;
+pub use features::resolve_features;
 pub use project::resolve_project;
 pub use run::resolve_run;
 pub use server::resolve_server;
@@ -51,6 +54,19 @@ pub fn resolve_project_from_file(
     }
 }
 
+pub fn resolve_features_from_file(
+    file: &SettingsFile,
+) -> Result<FeaturesSettings, Vec<ResolveError>> {
+    let mut errors = Vec::new();
+    let layer = file.features.as_ref().cloned().unwrap_or_default();
+    let resolved = resolve_features(&layer, &mut errors);
+    if errors.is_empty() {
+        Ok(resolved)
+    } else {
+        Err(errors)
+    }
+}
+
 pub fn resolve_run_from_file(file: &SettingsFile) -> Result<RunSettings, Vec<ResolveError>> {
     let mut errors = Vec::new();
     let layer = file.run.as_ref().cloned().unwrap_or_default();

lib/crates/fabro-config/tests/resolve_features.rs

@@ -0,0 +1,29 @@
+use fabro_config::resolve_features_from_file;
+use fabro_types::settings::SettingsFile;
+
+#[test]
+fn resolves_features_defaults_from_empty_settings() {
+    let settings = SettingsFile::default();
+
+    let features = resolve_features_from_file(&settings).expect("empty settings should resolve");
+
+    assert!(!features.session_sandboxes);
+}
+
+#[test]
+fn resolves_session_sandboxes_flag() {
+    let settings: SettingsFile = fabro_config::ConfigLayer::parse(
+        r#"
+_version = 1
+
+[features]
+session_sandboxes = true
+"#,
+    )
+    .expect("fixture should parse")
+    .into();
+
+    let features = resolve_features_from_file(&settings).expect("features should resolve");
+
+    assert!(features.session_sandboxes);
+}

lib/crates/fabro-server/src/web_auth.rs

@@ -147,8 +147,9 @@ fn json_response(status: StatusCode, body: serde_json::Value) -> Response {
 }
 
 fn features_json(settings: &SettingsFile) -> serde_json::Value {
-    let features = settings.features.as_ref();
-    let session_sandboxes = features.and_then(|f| f.session_sandboxes).unwrap_or(false);
+    let session_sandboxes = fabro_config::resolve_features_from_file(settings)
+        .map(|settings| settings.session_sandboxes)
+        .unwrap_or(false);
     let retros = fabro_config::resolve_run_from_file(settings)
         .map(|settings| settings.execution.retros)
         .unwrap_or(false);

lib/crates/fabro-types/src/settings/features.rs

@@ -5,6 +5,12 @@
 
 use serde::{Deserialize, Serialize};
 
+/// A structurally resolved `[features]` view for consumers.
+#[derive(Debug, Clone, Default, PartialEq)]
+pub struct FeaturesSettings {
+    pub session_sandboxes: bool,
+}
+
 /// A sparse `[features]` layer as it appears in a single settings file.
 ///
 /// Every field is an `Option<bool>` so layers can independently set or

lib/crates/fabro-types/src/settings/mod.rs

@@ -30,7 +30,7 @@ pub use cli::{
     CliUpdatesSettings,
 };
 pub use duration::{Duration, ParseDurationError};
-pub use features::FeaturesLayer;
+pub use features::{FeaturesLayer, FeaturesSettings};
 pub use interp::{InterpString, Provenance, ResolveEnvError, Resolved};
 pub use model_ref::{
     AmbiguousModelRef, ModelRef, ModelRegistry, ParseModelRefError, ResolvedModelRef,