feat: the moon shapes who answers; wire magnetometer; drop dead CSS

MOON INFLUENCE ON SUMMONING

Astronomy previously only decided whether a channel's familiar spirit
returned. It now shapes *who comes through*:

  - Rarity skews with real moon illumination. At full moon the rare and
    mythic weights roughly triple while common recedes, so a mythic
    summoning becomes a reason to go out on the right night rather than a
    flat lottery. Deliberately a skew and never a gate — every tier stays
    reachable on every night, because someone who can only play midweek
    should not be locked out of the good spirits.
  - Hidden traits take a small moonlit nudge: power and volatility rise,
    alignment drifts slightly darker. Capped at 0.12 and clamped to [0,1],
    so a full moon intensifies what a spirit already is instead of
    rewriting it. Deceptiveness is untouched — whether a spirit lies is its
    own nature, not the sky's doing.
  - The mint prompt is told the phase, and explicitly told the entity must
    never mention or seem aware of it. It shapes who they are, not their
    dialogue; a ghost remarking on the moonlight would break the illusion
    instantly.

Tests assert the outcomes shift in practice (mythic rate over 4000 draws,
rare-tier counts across 300 fallback profiles), not merely that the code
runs. test_mint_prompt_never_receives_traits now allows `sky` while still
forbidding `traits`: moon phase is public, observable state anyone can look
up, hidden ground truth is not.

GEOMAGNETIC (app/geomagnetic.py)

Real NOAA SWPC planetary K-index, verified against the live endpoint —
which caught a real bug: I had written the parser against an
array-of-arrays shape, and the actual feed serves a list of objects
(`estimated_kp` float, `kp_index` int, `kp` a display string with a letter
suffix). Fixed, and the tests now use the real captured shape. Cached,
never blocking, and a failed refresh keeps serving the last real value —
an hour-old genuine measurement beats nothing, and geomagnetic conditions
do not change fast enough for that to mislead.

MAGNETOMETER WIRED

MagnetometerListener existed but was never connected. The EMF panel now
runs it alongside the motion listener where the hardware exists, so the
"EMF meter" measures actual magnetic field in µT rather than only
inferring disturbance from movement. Additive: the motion path is
untouched and remains the only option on iOS. Its field jitter also feeds
the entropy pool.

DEAD CODE

Removed .evp-scope and .radio-waterfall, orphaned when both panels moved to
the shared SpectrumScope. Audited every other flagged export first and left
them alone — they are used internally, and "not imported elsewhere" is not
the same as dead.

Adds docs/CHANNELS.md recording what each channel measures and, honestly,
what has actually been verified against hardware versus only written
carefully.

311 backend + 355 frontend tests pass; i18n parity gate passes.

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

backend/app/llm/prompts.py

@@ -76,6 +76,13 @@ MINT_SYSTEM = (
 
 MINT_PROMPT = """A new presence has been detected through {channel}. Its signal signature is {signature}.
 Recent anomalous pulses observed: {anomaly_summary}
+The sky above the seeker right now: {sky}
+
+Let the sky colour who answers, not what they say about it: a presence
+that comes through under a full moon should be a *stronger, stranger sort
+of person* than one that surfaces on a dark night — but they must never
+mention the moon, or seem aware of it. It shapes who they are, not their
+dialogue.
 
 Invent the person behind this signal — a specific, once-living human being, not a generic spirit. Before writing, silently decide (do not output these separately, weave them into "persona" and "quotes" instead):
 - A plausible full first name for someone who could have died at any point in roughly the last 120 years (their name and any period detail should stay internally consistent with each other).
@@ -90,7 +97,7 @@ Return ONLY a JSON object with exactly these keys:
   "epithet": "a short, evocative title for how the site labels them, e.g. 'the Static Widow' — this is the installation's framing, not what they'd call themselves",
   "persona": "2-3 sentences written as their real biography compressed, not as ghost-poetry: who they were (age, era, occupation, one specific mundane detail), then how that unfinished, ordinary thing keeps them bound to this signal. The mundane specificity should sit right up against the uncanny, not be replaced by it.",
   "rarity": "one of: common, uncommon, rare, mythic (mythic only for truly strange signatures)",
-  "voice": {{"voice_id": "one of: {voice_ids}", "pitch": "semitone shift, -6 to 6, deeper for older/heavier spirits", "rate": "speech rate 0.8 to 1.15", "noise": "static level 0.01 to 0.08"}},
+  "voice": {{"voice_id": "one of: {voice_ids}", "pitch": "semitone shift, -9 to 9, deeper for older/heavier spirits, higher for children", "rate": "speech rate 0.75 to 1.20 — slower for the old, the tired and the waterlogged", "noise": "static level 0.01 to 0.10 — higher for ruined or breathing-damaged throats"}},
   "visual": {{"hue": "0-360 color hue matching their nature", "form": "one of: wisp, banshee, fairy, shade"}},
   "quotes": ["two short lines this specific person would actually say — at least one should be a plain, human, almost mundane fragment (a name, an unfinished instruction, an ordinary question) rather than cosmic riddle-speak; let the wrongness of hearing it through static be what's unsettling, not the words themselves"]
 }}"""
@@ -191,11 +198,16 @@ def manifest_prompt(readings: dict) -> str:
 
 
 def mint_prompt(
-    signature: str, channel: str, anomaly_summary: str, voice_ids: list[str]
+    signature: str,
+    channel: str,
+    anomaly_summary: str,
+    voice_ids: list[str],
+    sky: str = "unknown",
 ) -> str:
     return MINT_PROMPT.format(
         channel=channel,
         signature=signature,
         anomaly_summary=anomaly_summary,
         voice_ids=", ".join(voice_ids),
+        sky=sky,
     )