chore: migrate to v3, Doppler secrets, clean up legacy code

- Remove all pre-v3 code: scraper, ui-v2, backend v1, ios v1+v2, legacy CI workflows
- Flatten v3/ contents to repo root
- Add Doppler secrets management (project=libnovel, config=prd)
- Add justfile with doppler run wrappers for all docker compose commands
- Strip hardcoded env fallbacks from docker-compose.yml
- Add minimal README.md
- Clean up .gitignore

Caddyfile

@@ -0,0 +1,240 @@
+# v3/Caddyfile
+#
+# Caddy reverse proxy for LibNovel v3.
+# Custom build includes github.com/mholt/caddy-ratelimit.
+#
+# Environment variables consumed (set in docker-compose.yml):
+#   DOMAIN              — public hostname, e.g. libnovel.example.com
+#                         Use "localhost" for local dev (no TLS cert attempted).
+#   CADDY_ACME_EMAIL    — Let's Encrypt notification email (empty = no email)
+#
+# Routing rules (main domain):
+#   /health                        → backend:8080  (liveness probe)
+#   /scrape*                       → backend:8080  (Go admin scrape endpoints)
+#   /api/book-preview/*            → backend:8080  (live scrape, no store write)
+#   /api/chapter-text/*            → backend:8080  (chapter markdown from MinIO)
+#   /api/chapter-markdown/*        → backend:8080  (chapter markdown from MinIO)
+#   /api/reindex/*                 → backend:8080  (rebuild chapter index)
+#   /api/cover/*                   → backend:8080  (proxy cover image)
+#   /api/audio-proxy/*             → backend:8080  (proxy generated audio)
+#   /avatars/*                     → minio:9000    (presigned avatar GETs)
+#   /audio/*                       → minio:9000    (presigned audio GETs)
+#   /chapters/*                    → minio:9000    (presigned chapter GETs)
+#   /*  (everything else)          → ui:3000       (SvelteKit — handles all
+#                                                   remaining /api/* routes)
+#
+# Subdomain routing:
+#   feedback.libnovel.cc           → fider:3000    (user feedback / feature requests)
+#   errors.libnovel.cc             → glitchtip-web:8000  (error tracking)
+#   analytics.libnovel.cc          → umami:3000    (page analytics)
+#   logs.libnovel.cc               → dozzle:8080   (Docker log viewer)
+#   uptime.libnovel.cc             → uptime-kuma:3001  (uptime monitoring)
+#   push.libnovel.cc               → gotify:80     (push notifications)
+#
+# Routes intentionally removed from direct-to-backend:
+#   /api/scrape/*                  — SvelteKit has /api/scrape/ counterparts
+#                                    that enforce auth; routing directly would
+#                                    bypass SK middleware.
+#   /api/chapter-text-preview/*    — Same: SvelteKit owns
+#                                    /api/chapter-text-preview/[slug]/[n].
+#   /api/browse                    — Endpoint removed; browse snapshot system
+#                                    was deleted.
+{
+	# Email for Let's Encrypt ACME account registration.
+	# When CADDY_ACME_EMAIL is set this expands to e.g. "email you@example.com".
+	# When unset it expands to an empty string and is silently ignored.
+	{$CADDY_ACME_EMAIL:}
+
+	# CrowdSec bouncer — streams decisions from the CrowdSec LAPI every 15s.
+	# CROWDSEC_API_KEY is injected at runtime via crowdsec/.crowdsec.env.
+	# The default "disabled" placeholder makes the bouncer fail-open (warn,
+	# pass traffic) when no key is configured — Caddy still starts cleanly.
+	crowdsec {
+		api_url http://crowdsec:8080
+		api_key {$CROWDSEC_API_KEY:disabled}
+		ticker_interval 15s
+	}
+}
+
+(security_headers) {
+	header {
+		# Prevent clickjacking
+		X-Frame-Options "SAMEORIGIN"
+		# Prevent MIME-type sniffing
+		X-Content-Type-Options "nosniff"
+		# Minimal referrer info for cross-origin requests
+		Referrer-Policy "strict-origin-when-cross-origin"
+		# Restrict powerful browser features
+		Permissions-Policy "camera=(), microphone=(), geolocation=(), payment=()"
+		# Enforce HTTPS for 1 year (includeSubDomains)
+		Strict-Transport-Security "max-age=31536000; includeSubDomains"
+		# Enable XSS filter in older browsers
+		X-XSS-Protection "1; mode=block"
+		# Remove server identity header
+		-Server
+	}
+}
+
+{$DOMAIN:localhost} {
+	import security_headers
+
+	# ── CrowdSec bouncer ──────────────────────────────────────────────────────
+	# Checks every incoming request against CrowdSec decisions.
+	# Banned IPs receive a 403; all others pass through unchanged.
+	route {
+		crowdsec
+	}
+
+	# ── Rate limiting ─────────────────────────────────────────────────────────
+	# Auth endpoints: strict — 10 req/min per IP
+	rate_limit {
+		zone auth_zone {
+			match {
+				path /api/auth/login /api/auth/register /api/auth/change-password
+			}
+			key    {remote_host}
+			window 1m
+			events 10
+		}
+	}
+
+	# Admin scrape endpoints: moderate — 20 req/min per IP
+	rate_limit {
+		zone scrape_zone {
+			match {
+				path /scrape*
+			}
+			key    {remote_host}
+			window 1m
+			events 20
+		}
+	}
+
+	# Global: 300 req/min per IP (covers everything)
+	rate_limit {
+		zone global_zone {
+			key    {remote_host}
+			window 1m
+			events 300
+		}
+	}
+
+	# ── Liveness probe ────────────────────────────────────────────────────────
+	handle /health {
+		reverse_proxy backend:8080
+	}
+
+	# ── Scrape task creation (Go backend only) ────────────────────────────────
+	handle /scrape* {
+		reverse_proxy backend:8080
+	}
+
+	# ── Backend-only API paths ────────────────────────────────────────────────
+	# These paths are served exclusively by the Go backend and have no
+	# SvelteKit counterpart. Routing them here skips SK intentionally.
+	handle /api/book-preview/* {
+		reverse_proxy backend:8080
+	}
+	handle /api/chapter-text/* {
+		reverse_proxy backend:8080
+	}
+	handle /api/chapter-markdown/* {
+		reverse_proxy backend:8080
+	}
+	handle /api/reindex/* {
+		reverse_proxy backend:8080
+	}
+	handle /api/cover/* {
+		reverse_proxy backend:8080
+	}
+	handle /api/audio-proxy/* {
+		reverse_proxy backend:8080
+	}
+
+	# ── MinIO bucket paths (presigned URLs) ──────────────────────────────────
+	# MinIO path-style presigned URLs include the bucket name as the first
+	# path segment. MINIO_PUBLIC_ENDPOINT points here, so Caddy must proxy
+	# these paths directly to MinIO — no auth layer needed (the presigned
+	# signature itself enforces access and expiry).
+	handle /avatars/* {
+		reverse_proxy minio:9000
+	}
+	handle /audio/* {
+		reverse_proxy minio:9000
+	}
+	handle /chapters/* {
+		reverse_proxy minio:9000
+	}
+
+	# ── SvelteKit UI (catch-all — includes all remaining /api/* routes) ───────
+	handle {
+		reverse_proxy ui:3000
+	}
+
+	# ── Caddy-level error pages ───────────────────────────────────────────────
+	# These fire when the upstream (backend or ui) is completely unreachable.
+	# SvelteKit's own +error.svelte handles application-level errors (404, 500).
+	handle_errors 502 {
+		root * /srv/errors
+		rewrite * /502.html
+		file_server
+	}
+	handle_errors 503 {
+		root * /srv/errors
+		rewrite * /503.html
+		file_server
+	}
+	handle_errors 504 {
+		root * /srv/errors
+		rewrite * /504.html
+		file_server
+	}
+
+	# ── Logging ───────────────────────────────────────────────────────────────
+	# JSON log file read by CrowdSec for threat detection.
+	log {
+		output file /var/log/caddy/access.log {
+			roll_size     100MiB
+			roll_keep     5
+			roll_keep_for 720h
+		}
+		format json
+	}
+}
+
+# ── Fider: user feedback & feature requests ───────────────────────────────────
+feedback.libnovel.cc {
+	import security_headers
+	reverse_proxy fider:3000
+}
+
+# ── GlitchTip: error tracking ─────────────────────────────────────────────────
+errors.libnovel.cc {
+	import security_headers
+	reverse_proxy glitchtip-web:8000
+}
+
+# ── Umami: page analytics ─────────────────────────────────────────────────────
+analytics.libnovel.cc {
+	import security_headers
+	reverse_proxy umami:3000
+}
+
+# ── Dozzle: Docker log viewer ─────────────────────────────────────────────────
+logs.libnovel.cc {
+	import security_headers
+	reverse_proxy dozzle:8080
+}
+
+# ── Uptime Kuma: uptime monitoring ────────────────────────────────────────────
+uptime.libnovel.cc {
+	import security_headers
+	reverse_proxy uptime-kuma:3001
+}
+
+# ── Gotify: push notifications ────────────────────────────────────────────────
+push.libnovel.cc {
+	import security_headers
+	reverse_proxy gotify:80
+}
+}