Astro garden skeleton: Quartz-compatible URLs, Obsidian markdown, odometer homepage

- glob content loader over the vault's Digital_Garden with verbatim-path ids
- remark plugin: wikilinks, image embeds (wiki + relative md), callouts
- URL parity with live Quartz sitemap verified 102/102 (built set is a
  strict superset: +30 synthetic folder listings)
- KaTeX, lazy mermaid, shiki dual themes, quoted-string draft handling
- copy-assets resolves embeds vault-wide (fixes live-site 404s for
  Blog Scratch/assets images) into flat /assets/
- homepage odometer widget: fetches api.c0smere.net baseline, ticks at
  lifetime average rate, fail-closed hidden on error
- deploy/: nginx try_files config + compose (port 18100) + containerized
  build script for cyrion

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

deploy/build.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+# Containerized build for cyrion: mounts the Obsidian vault read-only and
+# writes dist/ into the repo checkout. Run from the repo root.
+set -eu
+
+VAULT="${VAULT:-/home/nox/docker/obsidian/vaults/weeslahw_coppermind}"
+
+docker run --rm \
+    -v "$(pwd):/app" \
+    -v "$VAULT:/content:ro" \
+    -e GARDEN_CONTENT=/content/Digital_Garden \
+    -e ASTRO_TELEMETRY_DISABLED=1 \
+    -w /app \
+    node:24-slim \
+    sh -c "npm ci && npm run build"