Phase 1 (#33)

* chore: Exclude CLAUDE.md from Cargo.toml

* feat: add callgraph module and integrate into main analysis flow

* feat: enhance CLI with new severity filtering and analysis modes

* feat: update CHANGELOG with recent enhancements and fixes to severity filtering and output handling

* feat: implement state-model dataflow analysis for resource lifecycle and auth state

* feat: enhance diagnostic output formatting and add evidence structure

* feat: implement attack surface ranking for diagnostics with scoring and sorting

* feat: add comprehensive documentation for installation, usage, and rules reference

* feat: add multiple language support for command execution and evaluation endpoints

* feat: implement inline suppression for findings using `nyx:ignore` comments

* feat: add confidence levels to AST patterns and update output structure

* feat: implement low-noise prioritization system with category filtering, rollup grouping, and configurable budgets

* feat: bump version to 0.4.0 and update changelog with new features and improvements

* feat: add dead code allowances to various functions in mod.rs and real_world_tests.rs

tests/fixtures/patterns/python/negative.py

@@ -0,0 +1,23 @@
+# Negative fixture: none of these should trigger security patterns.
+
+import subprocess
+import hashlib
+
+def safe_subprocess():
+    # No shell=True
+    subprocess.run(["ls", "-la"])
+
+def safe_hash():
+    hashlib.sha256(b"data")
+
+def safe_literal_query(cursor):
+    cursor.execute("SELECT COUNT(*) FROM users")
+
+def safe_yaml_load(data):
+    import yaml
+    yaml.safe_load(data)
+
+def safe_string_ops():
+    x = "hello"
+    y = x.upper()
+    z = len(y)