Add Phase 1 core infrastructure: event bus, state manager, engine, capture bus, tool manager, scheduler, resource monitor, kill switch

Core framework (8 files in core/) + BaseModule ABC (2 files in modules/):

- bus.py: Multiprocess-safe pub/sub event bus using mp.Queue with background dispatcher thread, 20 canonical event types
- state.py: SQLite persistent state with WAL mode, dedicated writer thread with 500ms coalesce, module status + generic key-value store
- engine.py: Module lifecycle manager with multiprocess model, dependency resolution (topological sort), hardware tier detection (opi_zero3/pi_zero/generic), resource budgeting, scope enforcement, engagement phase gating
- capture_bus.py: Single AF_PACKET socket packet demux with per-module subscriber queues, BPF filter matching, drop-oldest backpressure
- tool_manager.py: Subprocess lifecycle for external tools (bettercap/tcpdump/Responder/mitmproxy/ntlmrelayx) with exponential backoff restart, /proc resource monitoring, process disguise via prctl, health check callbacks, graceful SIGTERM->SIGKILL shutdown
- scheduler.py: Cron-like task scheduler with jitter, thread pool execution, enable/disable/run_now controls
- resource_monitor.py: System + per-process RAM/CPU/disk/thermal monitoring, OOM kill lowest-priority module, thermal shedding at 70C
- kill_switch.py: 7-phase wipe sequence (stop procs, corrective ARP, LUKS destroy, shred keys, zero-fill, clear RAM, reboot), boot flag for interrupted wipe resume, dead man's switch
- modules/base.py: BaseModule ABC with start/stop/status/configure/health_check interface contract

modules/base.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+"""Abstract base class for all BigBrother modules."""
+
+from abc import ABC, abstractmethod
+
+
+class BaseModule(ABC):
+    """Base class that all BigBrother modules must inherit from.
+
+    Each module runs as a separate process managed by the Engine.
+    """
+
+    name: str = "unnamed"
+    module_type: str = "passive"  # passive, active, stealth, intel, connectivity
+    priority: int = 100           # OOM priority (lower = more important)
+    dependencies: list = []       # Module names that must be running first
+    requires_root: bool = False
+
+    def __init__(self, bus, state, config, engine=None):
+        self.bus = bus
+        self.state = state
+        self.config = config
+        self.engine = engine
+        self._running = False
+        self._pid = None
+        self._start_time = None
+
+    @abstractmethod
+    def start(self) -> None:
+        """Start the module. Called by the engine in the module's own process."""
+        ...
+
+    @abstractmethod
+    def stop(self) -> None:
+        """Stop the module gracefully."""
+        ...
+
+    @abstractmethod
+    def status(self) -> dict:
+        """Return module status dict.
+
+        Returns:
+            {"running": bool, "pid": int, "uptime": float, "ram_mb": float, "cpu_pct": float}
+        """
+        ...
+
+    @abstractmethod
+    def configure(self, config: dict) -> None:
+        """Apply new configuration to a running module."""
+        ...
+
+    def health_check(self) -> bool:
+        """Check if the module is healthy. Override for custom checks."""
+        try:
+            return self.status().get("running", False)
+        except Exception:
+            return False