feat(sim): analytical Left HUD redesign + affect channel + no-cache

Left-brain HUD look-and-feel pass (judged by eye in the sim):
- corner-bracket targeting reticles (capped arms) replace plain boxes
- translucent label chips, legible over any frame
- two sensor channels: cyan detections (with deterministic confidence
  scores) vs amber measurements (center crosshair)
- bbox-sized "ANALYSIS . L{n} . {k} OBJ" status tag, escalating with Left

Affect channel (emotions in the HUD), per
docs/superpowers/specs/2026-06-22-affect-channel-hud-design.md:
- surfaces only when BOTH knobs up; strength = min(left, right)
- stable per-scene palette, more words appear with combined strength
- soft glowing violet words on their own opacity layer (the dream
  leaking into the machine's read); math in player/alteration.py
- forest/cosmos/abyss palettes in the manifest; 5 new unit tests

Simulator no-cache middleware so by-eye iteration never serves a stale
app.js / api response (fixes the latent "plan has affect but clip.affect
empty" stale-/api/clips bug).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

simulator/clips.py

@@ -26,6 +26,7 @@ class Clip:
     source: str
     right_variants: dict          # {"1": {"file": ...}, "4": {...}} (no "0")
     annotations: list             # [{"key", "box":[x,y,w,h], "min_level"}, ...]
+    affect: list                  # [{"key", "at":[x,y], "min_level"}, ...] (Left x Right)
     strings: dict                 # {"en": {key: text}}
 
     def variant_file(self, strength: int) -> str:
@@ -46,6 +47,7 @@ class Clip:
             "source": self.source,
             "right_variants": variants,
             "annotations": self.annotations,
+            "affect": self.affect,
             "strings": self.strings,
         }
 
@@ -59,6 +61,7 @@ def _clip_from_dict(d: dict[str, Any]) -> Clip:
         source=d.get("source", ""),
         right_variants=d.get("right_variants", {}),
         annotations=d.get("annotations", []),
+        affect=d.get("affect", []),
         strings=d.get("strings", {}),
     )