feat: the lens — the camera as a channel the dead look through

A new séance mode. The seeker opens their camera, presses "let it look",
and the entity speaks about what is ACTUALLY in the room — the configured
chat model (minicpm-v4.5:8b) is vision-capable, so this is real perception,
not invented description. Same principle as every other channel here: real
measurement first, interpretation second.

Verified live end-to-end through the real WebSocket: given a synthetic room
(pale doorway, red flame on dark boards), "Bessie L. Carter" reported the
gray rectangle and red square on a dark surface with faint shadows, then
misread it as her pen feeling heavy the night before Mr. Edgerton's birdseed
arrived. Accuracy followed by wrongness, which is the whole effect.

Privacy is the load-bearing design constraint, not a footnote:
- "Camera open" and "the entity saw something" are deliberately separate
  states. Opening the lens transmits NOTHING; only an explicit press sends
  one still. There is no timer and no background capture path.
- Frames are downscaled to 768px and JPEG-compressed client-side, then
  passed to the model and dropped. Never written to disk, never logged,
  never attached to an event row — only the resulting utterance is stored,
  exactly like any other thing a spirit says.
- The prompt forbids describing faces or guessing anyone's identity, age or
  appearance; a person present is spoken of only as a presence.
- A closed lens is covered by an opaque veil in the UI, so there is never
  ambiguity about whether the camera is live.

Robustness:
- CameraEye carries the same generation guard the EVP listener needed:
  closing during the permission prompt releases the late-arriving stream
  instead of letting the camera go live after teardown.
- Failures are classified (denied / insecure / absent / busy / unknown)
  rather than always blaming the seeker for a refusal.
- Scrying is the heaviest request this app makes of a CPU-only Ollama box,
  so it gets the tightest limiter of any channel (4/min/user, 8/min/IP).
- Frames are size-capped BEFORE reaching the queue, and a vision failure
  emits an error frame instead of killing the socket — both covered by
  tests asserting the model was never called.

10 new frontend tests, 5 new backend tests. 385 frontend + backend suites
pass; i18n parity holds across both languages.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/src/i18n/es.json

@@ -120,7 +120,8 @@
       "evp": "EVP",
       "radio": "Radio Espíritu",
       "ouija": "Ouija",
-      "emf": "CAMPO"
+      "emf": "CAMPO",
+      "camera": "LENTE"
     },
     "passive": "escucha pasiva",
     "summon": "INVOCAR",
@@ -165,7 +166,8 @@
       "evp": "el velo escucha a través de tu micrófono — préstale tu oído",
       "radio": "un sintonizador en la mano oye más lejos que el cable",
       "ouija": "pregunta abajo, o deja que el tablero derive",
-      "emf": "quédate quieto; el campo recuerda el movimiento"
+      "emf": "quédate quieto; el campo recuerda el movimiento",
+      "camera": "una lente muestra a los muertos tu habitación — nombrarán lo que ven, y lo confundirán con algo que perdieron."
     },
     "conditions": {
       "title": "CONDICIONES DEL VELO",
@@ -354,6 +356,28 @@
       "note": "tus contactos se desvanecen con la niebla —",
       "claim": "reclama un nombre para conservar tu códice",
       "dismiss": "deja que la niebla se lo lleve"
+    },
+    "camera": {
+      "previewLabel": "vista en directo de tu cámara",
+      "privacy": "nada sale de esta página hasta que dejes que mire — entonces se muestra un solo fotograma a la presencia, y nadie lo conserva.",
+      "open": "abrir la lente",
+      "opening": "abriendo la lente…",
+      "close": "cerrar la lente",
+      "flip": "girar la lente",
+      "look": "deja que mire",
+      "needEntity": "invoca primero a una presencia — aquí no hay nadie que mire.",
+      "fail": {
+        "deniedTitle": "la lente permanece cubierta",
+        "denied": "Este recipiente rechazó la cámara. Concede permiso de cámara en los ajustes del navegador y abre la lente de nuevo.",
+        "insecureTitle": "tierra sin consagrar",
+        "insecure": "Los muertos no mirarán por una lente insegura. Abre este sitio por su dirección https — o desde localhost — e inténtalo otra vez.",
+        "absentTitle": "ninguna lente por la que mirar",
+        "absent": "Este recipiente no tiene cámara que el velo pueda hallar. Conecta una, o acude a otro canal.",
+        "busyTitle": "la lente ya está en uso",
+        "busy": "Otro rito ya sostiene la cámara. Cierra lo que esté observando y abre la lente de nuevo.",
+        "unknownTitle": "la lente no se abre",
+        "unknown": "Algo rechazó la cámara y no dijo qué. Inténtalo de nuevo, o acude a otro canal."
+      }
     }
   },
   "codex": {