feat: add create-video.sh and four new AI-generated posts

Adds scripts/create-video.sh, which reads a post's prompt.{scene,
environment,style,video} frontmatter and generates its banner video via
Replicate's black-forest-labs/flux-3, extracting the first frame as the
preview PNG. Adds four new posts (the-clockwork-confessor,
the-last-lighthouse, the-ashen-choir, the-serpents-bargain) generated
through this pipeline.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012E2mmywuZyXmPBgSDtNdTL

content/posts/2026-09-16-the-serpents-bargain/index.md

@@ -0,0 +1,24 @@
+---
+title: "The Serpent's Bargain"
+description: "A sand-swallowed desert temple hides an ancient oracle whose lower body coils into a serpent of living dune-glass, offering a bargain no mortal has ever refused twice."
+date: 2026-09-13T13:00:00+02:00
+author: "valknar"
+featured: false
+categories:
+  - Dark
+  - Mythology
+tags:
+  - Oracle
+  - Serpent
+  - Desert Temple
+  - Sandstorm
+  - Ancient Ruins
+  - Mythology
+  - Bargain
+slug: the-serpents-bargain
+prompt:
+  scene: "An ancient oracle sits enthroned within the ruins of a sand-swallowed desert temple, her upper body regally human — bronzed skin, an elaborate headdress of fused gold and sun-bleached bone, dozens of thin gold bangles stacked along both forearms — while her lower body tapers into the immense coiled form of a serpent made of shifting, glasslike sand, its scales catching light like cut amber glass. Full-figure, low-angle shot emphasizing her height and the serpent coils pooling around a shattered stone altar. One hand extends forward, palm up, offering a small black hourglass in which the sand flows upward instead of down. Her eyes are solid gold, pupil-less, fixed on something just past the viewer. Half her serpent coil disappears into a fissure in the temple floor, from which more sand continuously pours."
+  environment: "The ruined inner sanctum of a temple buried to its rooftop in a vast desert, a shaft of harsh white sunlight cutting down through a collapsed section of ceiling to illuminate the oracle directly. Sandstone columns, cracked and half-swallowed, are carved with reliefs of serpents devouring their own tails. A sandstorm rages just beyond the temple's broken outer wall, visible through gaps as a churning ochre wall of wind, kept entirely at bay within the sanctum as if held by will alone. Loose sand rivers in slow, deliberate streams across the floor toward the oracle's coiled body rather than settling naturally. Broken statuary — headless guardian figures — lines the sanctum's edges, half-buried."
+  style: "Mythic desert surrealism rendered with the scale and reverence of ancient Egyptian and Mesopotamian temple imagery, crossed with an alien-oracle stillness. Palette of scorched gold, deep umber shadow, and pale desert-glare white, with the serpent coil rendered in translucent amber-glass sand that catches and refracts the shaft of sunlight. Hyper-realistic material fidelity: sun-cracked stone, hammered gold jewellery, individually rendered sand grains catching light along the serpent's coils. 8K photorealistic render, volumetric sunbeam with visible dust motes, monumental symmetrical composition."
+  video: "Sand pours continuously and visibly upward out of the inverted hourglass in a steady stream. The oracle's serpent coils shift and slither visibly, scales flexing and catching the light as they resettle. Loose sand streams visibly across the floor toward her in constant rivulets. Beyond the broken wall, the sandstorm churns and billows violently, its edge visibly roiling against the unseen barrier. The oracle's extended hand tilts further forward, offering the hourglass more insistently. Camera holds static throughout, but everything within the frame moves continuously."
+---