fix: resolve terminal display wobble and effect dimension stability

- Fix TerminalDisplay: add screen clear each frame (cursor home + erase down)
- Fix CameraStage: use set_canvas_size instead of read-only viewport properties
- Fix Glitch effect: preserve visible line lengths, remove cursor positioning
- Fix Fade effect: return original line when fade=0 instead of empty string
- Fix Noise effect: use input line length instead of terminal_width
- Remove HUD effect from all presets (redundant with border FPS display)
- Add regression tests for effect dimension stability
- Add docs/ARCHITECTURE.md with Mermaid diagrams
- Add mise tasks: diagram-ascii, diagram-validate, diagram-check
- Move markdown docs to docs/ (ARCHITECTURE, Refactor, hardware specs)
- Remove redundant requirements files (use pyproject.toml)
- Add *.dot and *.png to .gitignore

Closes #25

engine/pipeline/presets.py

@@ -80,7 +80,7 @@ DEMO_PRESET = PipelinePreset(
     source="headlines",
     display="pygame",
     camera="scroll",
-    effects=["noise", "fade", "glitch", "firehose", "hud"],
+    effects=["noise", "fade", "glitch", "firehose"],
 )
 
 POETRY_PRESET = PipelinePreset(
@@ -89,7 +89,7 @@ POETRY_PRESET = PipelinePreset(
     source="poetry",
     display="pygame",
     camera="scroll",
-    effects=["fade", "hud"],
+    effects=["fade"],
 )
 
 PIPELINE_VIZ_PRESET = PipelinePreset(
@@ -98,7 +98,7 @@ PIPELINE_VIZ_PRESET = PipelinePreset(
     source="pipeline",
     display="terminal",
     camera="trace",
-    effects=["hud"],
+    effects=[],
 )
 
 WEBSOCKET_PRESET = PipelinePreset(
@@ -107,7 +107,7 @@ WEBSOCKET_PRESET = PipelinePreset(
     source="headlines",
     display="websocket",
     camera="scroll",
-    effects=["noise", "fade", "glitch", "hud"],
+    effects=["noise", "fade", "glitch"],
 )
 
 SIXEL_PRESET = PipelinePreset(
@@ -116,7 +116,7 @@ SIXEL_PRESET = PipelinePreset(
     source="headlines",
     display="sixel",
     camera="scroll",
-    effects=["noise", "fade", "glitch", "hud"],
+    effects=["noise", "fade", "glitch"],
 )
 
 FIREHOSE_PRESET = PipelinePreset(
@@ -125,7 +125,7 @@ FIREHOSE_PRESET = PipelinePreset(
     source="headlines",
     display="pygame",
     camera="scroll",
-    effects=["noise", "fade", "glitch", "firehose", "hud"],
+    effects=["noise", "fade", "glitch", "firehose"],
 )