publisher: themed calendar, NIP-01 nostr adapter, gated brand images

- calendar: one draft per theme/channel (idempotent), rotated schedule
- human gate: approve() audited; AUTONOMOUS_MODE has no effect here by design
- nostr (primary): in-repo NIP-01 client (D4) — canonical serialization,
  sha256 id, BIP-340 schnorr sign via coincurve with zero aux randomness
  (deterministic), pure-python reference verification before publish,
  per-relay publish with isolated errors, event id stored as post_ref
- facebook/instagram adapters: exist but refuse to run unless explicitly
  enabled via env (default deployment never touches Meta)
- images: Pillow brand templates (bh gold / hc orange), 1080x1350,
  template-driven typeset design (not AI-generated media)
- failure isolation: config errors audited, item stays approved

tests: 12 new (event roundtrip+tamper, determinism, key validation,
calendar idempotence, approve gate, nostr happy path, future schedule,
clean config failure, disabled meta adapters, image render) — 41 total

cayceops/components/publisher/images.py

@@ -0,0 +1,72 @@
+"""Brand image templates (Pillow). 1080x1350 portrait, two brand styles.
+
+Deterministic, template-driven graphics — deliberately not AI-generated media
+(DECISIONS: nothing here trips AI-media disclosure requirements; it is typeset
+design). Fonts: Pillow's bundled default (scalable), so no system font deps.
+"""
+
+from __future__ import annotations
+
+import os
+
+from PIL import Image, ImageDraw, ImageFont
+
+WIDTH, HEIGHT = 1080, 1350
+
+_BRANDS = {
+    # bitcoinhotels — warm gold on near-black
+    "bh": {"bg": (20, 18, 16), "accent": (201, 168, 76), "text": (242, 236, 224), "muted": (150, 140, 120)},
+    # hardcap — bitcoin orange on cool black
+    "hc": {"bg": (13, 13, 16), "accent": (247, 147, 26), "text": (250, 250, 250), "muted": (120, 120, 130)},
+}
+
+
+def _font(size: int, bold: bool = False):
+    # Pillow >=10: load_default(size=...) returns a scalable bundled font
+    return ImageFont.load_default(size=size)
+
+
+def _vgrad(top: tuple, bottom: tuple) -> Image.Image:
+    """Simple two-color vertical gradient."""
+    img = Image.new("RGB", (WIDTH, HEIGHT))
+    for y in range(HEIGHT):
+        t = y / (HEIGHT - 1)
+        row = tuple(int(top[i] + (bottom[i] - top[i]) * t) for i in range(3))
+        ImageDraw.Draw(img).line([(0, y), (WIDTH, y)], fill=row)
+    return img
+
+
+def render_brand_image(
+    *,
+    brand: str = "bh",
+    kicker: str | None,
+    lines: list[str],
+    tagline: list[str] | None = None,
+    url: str | None = None,
+    out_path: str,
+) -> str:
+    """Render one branded poster. Returns out_path. Raises on unknown brand."""
+    if brand not in _BRANDS:
+        raise ValueError(f"unknown brand {brand!r} (have: {sorted(_BRANDS)})")
+    palette = _BRANDS[brand]
+    img = _vgrad(palette["bg"], tuple(max(0, c - 8) for c in palette["bg"]))
+    draw = ImageDraw.Draw(img)
+
+    x, y = 90, 240
+    if kicker:
+        draw.text((x, y), kicker, font=_font(40), fill=palette["muted"])
+        y += 110
+    for line in lines:
+        draw.text((x, y), line, font=_font(96, bold=True), fill=palette["text"])
+        y += 118
+    y += 24
+    for t in tagline or []:
+        draw.text((x, y), t, font=_font(38), fill=palette["muted"])
+        y += 58
+    draw.rectangle([x, y + 30, x + 470, y + 33], fill=palette["accent"])
+    if url:
+        draw.text((x, y + 110), url, font=_font(44), fill=palette["accent"])
+
+    os.makedirs(os.path.dirname(out_path) or ".", exist_ok=True)
+    img.save(out_path, "JPEG", quality=92)
+    return out_path