feat: add Kokoro TTS, ranking page, direct HTTP strategy, and chapter-number fix

- Add Kokoro-FastAPI TTS integration to the chapter reader UI:
  - Browser-side MSE streaming with paragraph-level click-to-start
  - Voice selector, speed slider, auto-next with prefetch of the next chapter
  - New GET /ui/chapter-text endpoint that strips Markdown and serves plain text

- Add ranking page (novelfire /ranking scraper, WriteRanking/ReadRankingItems
  in writer, GET /ranking + POST /ranking/refresh + GET /ranking/view routes)
  with local-library annotation and one-click scrape buttons

- Add StrategyDirect (plain HTTP client) as a new browser strategy; the
  default strategy is now 'direct' for chapter fetching and 'content'
  for chapter-list URL retrieval (split via BROWSERLESS_URL_STRATEGY)

- Fix chapter numbering bug: numbers are now derived from the URL path
  (/chapter-N) rather than list position, correcting newest-first ordering

- Add 'refresh <slug>' CLI sub-command to re-scrape a book from its saved
  source_url without knowing the original URL

- Extend NovelScraper interface with RankingProvider (ScrapeRanking)

- Tune scraper timeouts: wait-for-selector reduced to 5 s, GotoOptions
  timeout set to 60 s, content/scrape client defaults raised to 90 s

- Add cover extraction fix (figure.cover > img rather than bare img.cover)

- Add AGENTS.md and .aiignore for AI tooling context

- Add integration tests for browser client and novelfire scraper (build
  tag: integration) and unit tests for chapterNumberFromURL and pagination

.env.example

@@ -13,11 +13,29 @@ BROWSERLESS_QUEUED=100
 # Per-session timeout in ms
 BROWSERLESS_TIMEOUT=60000
 
-# Which Browserless strategy the scraper uses: content | scrape | cdp
-BROWSERLESS_STRATEGY=content
+# Optional webhook URL for Browserless error alerts (leave empty to disable)
+ERROR_ALERT_URL=
+
+# Which Browserless strategy the scraper uses: content | scrape | cdp | direct
+BROWSERLESS_STRATEGY=direct
+
+# Strategy for URL retrieval (chapter list). Uses browserless content strategy by default.
+# Set to direct to use plain HTTP, or content/scrape/cdp for browserless.
+BROWSERLESS_URL_STRATEGY=content
 
 # Chapter worker goroutines (0 = NumCPU inside the container)
 SCRAPER_WORKERS=0
 
 # Host path to mount as the static output directory
 STATIC_ROOT=./static/books
+
+# ── Kokoro-FastAPI TTS ────────────────────────────────────────────────────────
+# Base URL for the Kokoro-FastAPI service.  When running via docker-compose the
+# default (http://kokoro:8880) is wired in automatically; override here only if
+# you are pointing at an external or GPU instance.
+KOKORO_URL=http://kokoro:8880
+
+# Default voice used for chapter narration.
+# Single voices: af_bella, af_sky, af_heart, am_adam, …
+# Mixed voices:  af_bella+af_sky  or  af_bella(2)+af_sky(1)  (weighted blend)
+KOKORO_VOICE=af_bella