Add studio sdlc command for SDLC maintenance pipeline

Implements a pipeline that orchestrates 7 g3 agents in sequence:
1. euler - dependency graph and hotspots analysis
2. breaker - whitebox exploration and edge-case discovery
3. hopper - deep testing and regression integrity
4. fowler - refactoring to deduplicate and reduce complexity
5. carmack - in-place rewriting for readability and concision
6. lamport - human-readable documentation and validation
7. huffman - semantic compression of memory

Features:
- Commit cursor tracking (--from flag to set starting point)
- Crash recovery (resumes from last incomplete stage)
- Git worktree isolation for all pipeline work
- Visual pipeline display with status icons
- Summary generation saved to .g3/sessions/sdlc/
- Pipeline state persisted to analysis/sdlc/pipeline.json

CLI:
- studio sdlc run [-c N] [--from COMMIT]
- studio sdlc status
- studio sdlc reset

Also adds huffman agent to embedded agents list.

crates/g3-cli/src/embedded_agents.rs

@@ -19,6 +19,7 @@ static EMBEDDED_AGENTS: &[(&str, &str)] = &[
     ("euler", include_str!("../../../agents/euler.md")),
     ("fowler", include_str!("../../../agents/fowler.md")),
     ("hopper", include_str!("../../../agents/hopper.md")),
+    ("huffman", include_str!("../../../agents/huffman.md")),
     ("lamport", include_str!("../../../agents/lamport.md")),
     ("scout", include_str!("../../../agents/scout.md")),
 ];
@@ -88,7 +89,7 @@ mod tests {
     #[test]
     fn test_embedded_agents_exist() {
         // Verify all expected agents are embedded
-        let expected = ["breaker", "carmack", "euler", "fowler", "hopper", "lamport", "scout"];
+        let expected = ["breaker", "carmack", "euler", "fowler", "hopper", "huffman", "lamport", "scout"];
         for name in expected {
             assert!(
                 get_embedded_agent(name).is_some(),
@@ -101,7 +102,7 @@ mod tests {
     #[test]
     fn test_list_embedded_agents() {
         let agents = list_embedded_agents();
-        assert!(agents.len() >= 7, "Should have at least 7 embedded agents");
+        assert!(agents.len() >= 8, "Should have at least 8 embedded agents");
         assert!(agents.contains(&"carmack"));
         assert!(agents.contains(&"hopper"));
     }