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/2026-09-13-the-clockwork-confessor/index.md

@@ -0,0 +1,24 @@
+---
+title: "The Clockwork Confessor"
+description: "A towering brass automaton priest hears confession in a gaslit cathedral, its porcelain saint's mask cracked, gears turning beneath tarnished metal as candlelight gutters through the nave."
+date: 2026-09-13T10:00:00+02:00
+author: "valknar"
+featured: true
+categories:
+  - Dark
+  - Steampunk
+tags:
+  - Automaton
+  - Clockwork
+  - Cathedral
+  - Confession
+  - Brass
+  - Gothic
+  - Inquisition
+slug: the-clockwork-confessor
+prompt:
+  scene: "A towering brass-and-iron automaton priest kneels within an ornate confessional booth of black oak and wrought iron, half-hidden behind a velvet curtain torn at the hem. Full-figure, three-quarter shot from within the confessional's opposite side, looking through the wooden lattice screen. The automaton's body is a masterwork of exposed clockwork: articulated brass ribs housing spinning escapements, a chest cavity where a slow pendulum swings behind smoked glass, tarnished copper tubing running along both arms venting faint puffs of steam with every mechanical breath. Its hands, folded in a gesture of benediction, are long articulated fingers of blackened steel ending in delicate porcelain fingertips. Its face is a cracked porcelain mask shaped into the serene, downturned features of a saint — one long fissure running from brow to jaw, revealing a single glowing amber optic lens beneath. It holds an ancient leather-bound book, pages fluttering slightly though there is no wind. The mask tilts slowly toward the lattice, listening."
+  environment: "The interior of a vast, decaying Gothic cathedral repurposed as a clockwork sanctuary. Soaring ribbed vaults disappear into darkness overhead, hung with rusted gears the size of cartwheels suspended on chains, turning almost imperceptibly in unison with some unseen mechanism. Rows of empty pews stretch into gloom, dust thick on every surface, candlewax pooled in ancient drifts along the aisle. Stained-glass windows depict saints rendered as machines — halos of gear teeth, wings of articulated brass feathers — filtering fractured amber and blue light across the stone floor. A single overturned prayer kneeler lies near the confessional. Somewhere unseen, a great pendulum clock ticks, its sound echoing through the nave like a heartbeat the building cannot stop."
+  style: "Dark steampunk gothic realism. The visual language of Guillermo del Toro's cathedral interiors fused with Jean-Pierre Jeunet's warm-brass mechanical detailing. Chiaroscuro lighting: deep cathedral shadow pierced by shafts of dusty amber candlelight and cold blue stained-glass spill. Hyper-realistic material rendering — oxidised copper, oil-black iron, cracked antique porcelain with fine craquelure, aged velvet with worn nap. 8K photorealistic render, subtle film grain, anamorphic lens flare where light catches brass edges, painterly gothic composition reminiscent of Baroque religious portraiture."
+  video: "The suspended gears overhead rotate visibly and continuously, their brass teeth catching shifting light. Thick steam billows rhythmically from the automaton's neck vents in visible bursts. The automaton visibly turns its head upward toward the gears, then lowers it back to the book, the crack in its mask glinting as it moves. Its brass fingers turn a page of the open book. Candlelight flickers and dances across every surface, casting moving shadows. Camera holds static throughout, but everything within the frame moves continuously."
+---