feat: add --scan-mode CLI option with quick/standard/deep modes

Introduces scan mode selection to control testing depth and methodology:
- quick: optimized for CI/CD, focuses on recent changes and high-impact vulns
- standard: balanced coverage with systematic methodology
- deep: exhaustive testing with hierarchical agent swarm (now default)

Each mode has dedicated prompt modules with detailed pentesting guidelines
covering reconnaissance, mapping, business logic analysis, exploitation,
and vulnerability chaining strategies.

Closes #152

strix/interface/cli.py

@@ -66,6 +66,8 @@ async def run_cli(args: Any) -> None:  # noqa: PLR0915
     console.print(startup_panel)
     console.print()
 
+    scan_mode = getattr(args, "scan_mode", "deep")
+
     scan_config = {
         "scan_id": args.run_name,
         "targets": args.targets_info,
@@ -73,7 +75,7 @@ async def run_cli(args: Any) -> None:  # noqa: PLR0915
         "run_name": args.run_name,
     }
 
-    llm_config = LLMConfig()
+    llm_config = LLMConfig(scan_mode=scan_mode)
     agent_config = {
         "llm_config": llm_config,
         "max_iterations": 300,

strix/interface/main.py

@@ -312,6 +312,21 @@ Examples:
         ),
     )
 
+    parser.add_argument(
+        "-m",
+        "--scan-mode",
+        type=str,
+        choices=["quick", "standard", "deep"],
+        default="deep",
+        help=(
+            "Scan mode: "
+            "'quick' for fast CI/CD checks, "
+            "'standard' for routine testing, "
+            "'deep' for thorough security reviews (default). "
+            "Default: deep."
+        ),
+    )
+
     args = parser.parse_args()
 
     if args.instruction and args.instruction_file:

strix/interface/tui.py

@@ -319,7 +319,8 @@ class StrixTUIApp(App):  # type: ignore[misc]
         }
 
     def _build_agent_config(self, args: argparse.Namespace) -> dict[str, Any]:
-        llm_config = LLMConfig()
+        scan_mode = getattr(args, "scan_mode", "deep")
+        llm_config = LLMConfig(scan_mode=scan_mode)
 
         config = {
             "llm_config": llm_config,