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/2026-09-14-the-last-lighthouse/index.md

@@ -0,0 +1,24 @@
+---
+title: "The Last Lighthouse"
+description: "A drowned lighthouse keeper's ghost still tends the lamp atop a crumbling tower, the flooded fishing village below lit by bioluminescent tides that remember every ship it failed to save."
+date: 2026-09-13T11:00:00+02:00
+author: "valknar"
+featured: false
+categories:
+  - Dark
+  - Horror
+tags:
+  - Lighthouse
+  - Ghost
+  - Ocean
+  - Drowned Village
+  - Storm
+  - Nautical
+  - Bioluminescence
+slug: the-last-lighthouse
+prompt:
+  scene: "A translucent, spectral lighthouse keeper stands within the lamp room at the top of a crumbling stone lighthouse, half-submerged in a storm-flooded sea. Full-figure, wide interior shot looking up through the shattered lamp-room glass toward the figure. The keeper is rendered in wisps of pale blue-white light, oilskin coat and sou'wester hat frayed into trailing luminous vapour at the edges, face obscured beneath the hat's brim save for two faint points of lamplight where eyes should be. One translucent hand rests on the great brass Fresnel lens, its prisms cracked but still turning with a slow, grinding creak, casting a rotating beam of pale gold light out into the storm. Barnacles and dead coral cling to the ironwork railing around him, dripping with seawater that never quite touches his form. He does not react to the storm outside."
+  environment: "A once-thriving fishing village now drowned to its rooftops, visible below through the tower's broken windows — church spire and cottage roofs breaking the black water like tombstones, strings of dead fishing nets tangled in chimney stacks. The sea itself glows faintly bioluminescent blue-green beneath the storm swell, illuminating drowned boats and a single bell tower whose bell still tolls, moved by the current. Lightning forks across a bruised purple-black sky heavy with rain. Gulls wheel and vanish into the dark. The lighthouse tower itself is crumbling, stone slick with salt and moss, iron railings rusted to lace, waves crashing against its base high enough to nearly reach the lamp room."
+  style: "Painterly maritime gothic horror. The atmosphere of The Lighthouse (2019) crossed with bioluminescent deep-sea dread. Cold, desaturated palette dominated by storm-grey and deep indigo, cut through with the warm amber sweep of the lighthouse beam and the eerie cyan glow of the bioluminescent sea. Photorealistic water and glass rendering, volumetric rain and sea-spray, the ghost rendered with soft translucent luminosity that never fully resolves into solid form. 8K cinematic render, heavy atmospheric fog, long lens compression, restrained color grade evoking dread rather than gore."
+  video: "The great Fresnel lens rotates continuously and visibly, its beam sweeping fully around the tower and across the drowned village rooftops below. Rain lashes down in constant, heavy sheets, splattering visibly against the broken glass. Waves crash rhythmically against the tower's base, throwing spray upward. Lightning flashes repeatedly, strobing the storm. The ghostly keeper's translucent form drifts and billows continuously like smoke caught in wind. The distant bell swings and tolls again and again as the current moves it. Camera holds static throughout, but everything within the frame moves continuously."
+---