feat: Implement pipeline hot-rebuild and camera improvements

- Fixes issue #45: Add state property to EffectContext for motionblur/afterimage effects
- Fixes issue #44: Reset camera bounce direction state in reset() method
- Fixes issue #43: Implement pipeline hot-rebuild with state preservation
- Adds radial camera mode for polar coordinate scanning
- Adds afterimage and motionblur effects
- Adds acceptance tests for camera and pipeline rebuild

Closes #43, #44, #45

engine/display/backends/terminal.py

@@ -3,7 +3,6 @@ ANSI terminal display backend.
 """
 
 import os
-import time
 
 
 class TerminalDisplay:
@@ -89,16 +88,8 @@ class TerminalDisplay:
 
         from engine.display import get_monitor, render_border
 
-        t0 = time.perf_counter()
-
-        # FPS limiting - skip frame if we're going too fast
-        if self._frame_period > 0:
-            now = time.perf_counter()
-            elapsed = now - self._last_frame_time
-            if elapsed < self._frame_period:
-                # Skip this frame - too soon
-                return
-            self._last_frame_time = now
+        # Note: Frame rate limiting is handled by the caller (e.g., FrameTimer).
+        # This display renders every frame it receives.
 
         # Get metrics for border display
         fps = 0.0
@@ -117,15 +108,9 @@ class TerminalDisplay:
             buffer = render_border(buffer, self.width, self.height, fps, frame_time)
 
         # Write buffer with cursor home + erase down to avoid flicker
-        # \033[H = cursor home, \033[J = erase from cursor to end of screen
         output = "\033[H\033[J" + "".join(buffer)
         sys.stdout.buffer.write(output.encode())
         sys.stdout.flush()
-        elapsed_ms = (time.perf_counter() - t0) * 1000
-
-        if monitor:
-            chars_in = sum(len(line) for line in buffer)
-            monitor.record_effect("terminal_display", elapsed_ms, chars_in, chars_in)
 
     def clear(self) -> None:
         from engine.terminal import CLR