docs: document Options, IsProbablyReaderable, and benchmark workflow

README now shows how to pass Options to FromReader, how to use the
IsProbablyReaderable pre-check, and how to run the benchmark suite
added in 44f1074. The Options example mirrors the godoc fields added
in 0bc9d1e so that public API docs and the README stay in sync.

Author: miclle

README.md

@@ -102,6 +102,54 @@ func main() {
 }
 ```
 
+### Options
+
+`FromReader` accepts an optional `*Options` to mirror the upstream parser
+configuration knobs:
+
+```go
+opts := &readability.Options{
+	CharThreshold:     500,                                    // skip docs shorter than 500 chars
+	ClassesToPreserve: []string{"caption", "highlight"},      // extra classes kept during cleanup
+	KeepClasses:       false,                                  // true keeps every class attribute
+	NbTopCandidates:   5,                                      // candidate pool size during scoring
+	DisableJSONLD:     false,                                  // skip JSON-LD metadata extraction
+	AllowedVideoRegex: nil,                                    // override built-in video allow list
+	MaxElemsToParse:   0,                                      // > 0 aborts on huge documents with ErrTooManyElements
+}
+article, err := readability.FromReader(f, pageURL, opts)
+```
+
+When `MaxElemsToParse` is exceeded the call returns `readability.ErrTooManyElements`.
+
+### Probing readerability
+
+For a fast pre-check that does not run the full extractor:
+
+```go
+ok, err := readability.IsProbablyReaderable(f)
+if err != nil {
+	log.Fatal(err)
+}
+if !ok {
+	return
+}
+```
+
+`IsProbablyReaderable` accepts an optional `ReaderableOptions` to tune
+`MinContentLength` and `MinScore`.
+
+## Benchmarks
+
+A benchmark suite covering small / medium / large / visibility-heavy fixtures
+lives in `bench_test.go`:
+
+```sh
+go test -bench=. -benchmem -benchtime=2s -run=^$
+```
+
+Use the suite as a baseline before / after performance-sensitive changes.
+
 ## Upstream Test Data
 
 Compatibility fixtures under `testdata/test-pages` are copied from