feat: configurable corpus base dir + Bascule dev config

- corpus_check_with_base(): accepts explicit base directory
- corpus_check(): still defaults to /opt/substrate/corpus
- Improved corpus test with actual Allowed/Denied assertions
- Updated bascule-dev.toml with [gsap] section and shell_command

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config/bascule-dev.toml

@@ -6,8 +6,15 @@ ca_key_path = "/dev/null"
 host_key_path = "/dev/null"
 dispatch_mode = "direct"
 auth_mode = "permissive"
+shell_command = "/home/tking/.local/bin/gsh"
 
 [elevation]
 operator_ttl_secs = 3600
 admin_ttl_secs = 1800
 emergency_ttl_secs = 900
+
+[gsap]
+# broker_url = "http://localhost:8091"
+# token = ""
+default_corpus_cid = "sha256:dev-jumphost"
+default_accord_template = "shell-exec"

libgsh/src/corpus.rs

@@ -15,15 +15,24 @@ pub enum CorpusCheckResult {
     Denied { command: String, corpus_cid: String },
 }
 
+/// Default corpus base directory.
+pub const DEFAULT_CORPUS_BASE: &str = "/opt/substrate/corpus";
+
 /// Check if a command is authorized in the corpus directory.
 ///
+/// `base_dir` overrides the default /opt/substrate/corpus (set via GSH_CORPUS_DIR env).
 /// Returns Ok(result) always. Caller decides whether to block on Denied.
 pub fn corpus_check(corpus_cid: &str, command: &str) -> CorpusCheckResult {
+    corpus_check_with_base(corpus_cid, command, DEFAULT_CORPUS_BASE)
+}
+
+/// corpus_check with an explicit base directory.
+pub fn corpus_check_with_base(corpus_cid: &str, command: &str, base_dir: &str) -> CorpusCheckResult {
     if corpus_cid == "sha256:ungoverned" {
         return CorpusCheckResult::Ungoverned;
     }
 
-    let corpus_dir = Path::new("/opt/substrate/corpus").join(corpus_cid);
+    let corpus_dir = Path::new(base_dir).join(corpus_cid);
     if !corpus_dir.exists() {
         return CorpusCheckResult::NotMounted;
     }
@@ -73,10 +82,14 @@ mod tests {
         std::fs::create_dir_all(&corpus_dir).unwrap();
         std::fs::write(corpus_dir.join("kubectl"), "").unwrap();
 
-        // Can't easily test with /opt/substrate/corpus, but the logic is straightforward.
-        // The unit test validates the command name extraction:
-        let cmd = "kubectl get pods -n test";
-        let name = cmd.split_whitespace().next().unwrap();
-        assert_eq!(name, "kubectl");
+        let base = dir.path().to_str().unwrap();
+        assert!(matches!(
+            corpus_check_with_base(cid, "kubectl get pods -n test", base),
+            CorpusCheckResult::Allowed
+        ));
+        assert!(matches!(
+            corpus_check_with_base(cid, "helm install", base),
+            CorpusCheckResult::Denied { .. }
+        ));
     }
 }

libgsh/src/lib.rs

@@ -9,7 +9,7 @@ pub mod session;
 pub use ac::{AcValidationError, AuthorizationContext};
 pub use classifier::{classify_command, CommandClass, FREE_COMMANDS};
 pub use config::GshConfig;
-pub use corpus::{corpus_check, CorpusCheckResult};
+pub use corpus::{corpus_check, corpus_check_with_base, CorpusCheckResult, DEFAULT_CORPUS_BASE};
 pub use cr::{post_cr, CrResult};
 pub use registry::ConsumedRegistry;
 pub use session::SessionState;