feat: add interactive conventional commit workflow with jj-lib backend

Replace CLI executor with jj-lib integration, implement full interactive
commit workflow via prompts, and add mock infrastructure for testing.
Add CLI integration tests and error handling tests.

deny.toml

@@ -10,8 +10,11 @@ ignore = []
 allow = [
   "Apache-2.0 WITH LLVM-exception",
   "Apache-2.0",
+  "BSD-3-Clause",
   "MIT",
+  "MPL-2.0",
   "Unicode-3.0",
+  "Zlib",
 ]
 confidence-threshold = 0.8
 exceptions = []
@@ -22,9 +25,9 @@ registries = []
 
 [bans]
 multiple-versions = "allow"
-wildcards = "allow"
+wildcards = "deny"
 highlight = "all"
-workspace-default-features = "allow"
+workspace-default-features = "deny"
 external-default-features = "allow"
 allow = []
 deny = []