Added experimental control flow analysis and syntax classification for rust lang (#22)

* Introduce control flow graph (CFG) support:

- Added `cfg.rs` with CFG generation and analysis utilities.
- Integrated `petgraph` library for graph-based computations.
- Updated `ast.rs` to utilize CFG for function analysis.
- Modified `Cargo.toml` and `Cargo.lock` to include new dependencies.
- Improved static analysis with taint tracking through CFG paths.

* feat: enhance control flow analysis with taint tracking and node labeling

* feat: improve control flow graph with enhanced node handling and new tests

* Remove unnecessary reference marker in `byte_offset_to_point` comment.

* Remove unnecessary reference marker in `byte_offset_to_point` comment.

* Refactor `ast.rs` for performance and clarity; enhance `cfg.rs` with recursive CFG generation and improved classification logic for AST analysis.

* Refactor CFG and taint tracking logic:

- Enhanced `cfg.rs` with inline helper function `text_of` for cleaner UTF-8 handling in AST nodes.
- Expanded `labels.rs` rules with detailed `Sources`, `Sanitizers`, and `Sinks` for improved classification.
- Refined `push_node` to handle method call expressions with object-function pairing.
- Simplified code handling in trivia skipping and debug-only logic.

* Enhance `cfg.rs` with `first_call_ident` helper and improve identifier extraction logic in `push_node`.

* Add targeted CFG taint-tracking tests to enhance analysis coverage.

* Enhance CFG generation with loop expression handling and improve taint tracking logic. Add new sanitization example in `examples/sanitize/example.rs`.

* Update README with installation instructions for Cargo and GitHub releases.

* Expand taint-tracking with precise `def-use` computation and enhance `labels.rs` for detailed classification. Extend `examples/sanitize` with realistic scenarios demonstrating new rules.

* Refactor `labels.rs`:

- Removed redundant `LabelRule` entries for cleaner rule definitions.
- Adjusted matching logic to prioritize suffix and prefix matches effectively.

* Refactor `labels.rs`:

- Removed redundant `LabelRule` entries for cleaner rule definitions.
- Adjusted matching logic to prioritize suffix and prefix matches effectively.

* Add test for taint tracking with multiple sources in `cfg.rs`.

* Add `function_summaries` table and implement summary upsert/load methods. Refactor to handle summary storage and retrieval efficiently, with placeholder clean/drop logic.

* refactor: split `labels.rs` into modular structure with language-specific files

* refactor: split `labels.rs` into modular structure with language-specific files

* refactor: clean up SQL table definitions in `database.rs` for better readability

* refactor: simplify CFG structure by removing lifetime parameters and enhancing taint metadata handling

* refactor: update TODO comments in `cfg.rs` to clarify future enhancements for cap labels and function details

* refactor: remove redundant header from README.md for improved clarity

* feat: add PHF-based syntax classifiers and Kind enum for efficient syntax mapping across languages

* feat: introduce analysis modes for enhanced scanner configuration and diagnostics

* feat: define Kind enum for syntax classification in control flow analysis

* feat: bump version to 0.2.0-alpha and update CHANGELOG for new features and fixes

* refactor: clean up imports and formatting in AST and CFG modules for improved readability

* refactor: simplify function signatures and improve code readability in CFG and module files

* fix: correct rayon_thread_stack_size comment to reflect actual value of 8 MiB

* refactor: update string formatting in clean and project modules for consistency

* refactor: fix indentation in clean.rs for improved readability

---------

Co-authored-by: elipeter <eli.peter@es.fcm.travel>

src/patterns/mod.rs

@@ -92,7 +92,7 @@ static REGISTRY: Lazy<HashMap<&'static str, &'static [Pattern]>> = Lazy::new(||
     m.insert("cpp", cpp::PATTERNS);
     m.insert("c++", cpp::PATTERNS);
 
-    // ---- Other languages in the folder ----
+    // ---- Other patterns in the folder ----
     m.insert("java", java::PATTERNS);
     m.insert("go", go::PATTERNS);
     m.insert("php", php::PATTERNS);
@@ -101,14 +101,14 @@ static REGISTRY: Lazy<HashMap<&'static str, &'static [Pattern]>> = Lazy::new(||
     m.insert("ruby", ruby::PATTERNS);
     m.insert("rb", ruby::PATTERNS);
 
-    tracing::debug!("AST-pattern registry initialised ({} languages)", m.len());
+    tracing::debug!("AST-pattern registry initialised ({} patterns)", m.len());
 
     m
 });
 
 /// Return all patterns for the requested language (case-insensitive).
 ///
-/// Unknown languages yield an **empty** `Vec`.
+/// Unknown patterns yield an **empty** `Vec`.
 pub fn load(lang: &str) -> Vec<Pattern> {
     let key = lang.to_ascii_lowercase();
     REGISTRY.get(key.as_str()).copied().unwrap_or(&[]).to_vec()