Spec #135: owner data-correction actions — Latest Chapter, series_url, Cover, orphan removal (#156)

Implements spec #135 (spec 2 of 4, derived from wayfinder map #114; decisions settled in #120/#121/#125/#131). Blocked-by #134 is merged, so this lands on `main`.

Four owner actions the dashboard can now perform, one ticket each:

- **#149** — Latest Chapter correction: one numeric input, overwritten by the next machine write.
- **#151** — Series URL repair: owner-typed, gated by the poller's own fetch gate.
- **#150 / #153 / #154** — Cover replacement: addresses derived from bytes (`#150`), a Forced Poll replaces the Cover while an ordinary pass still only fills a blank one (`#153`), and byte reclamation is one guarded helper, file first / covers row last (`#154`).
- **#155** — Orphan removal: one Series at a time, with the foreign key as the guard.

Plus **#152** — Latest Chapter provenance: one derived line naming the actor class, so an owner can tell a hand-edited number from a machine read.

- Migration `0015_latest_correction.sql` adds the correction/provenance columns; `0009` now derives cover addresses from bytes.
- ADR `0014-cover-addresses-from-bytes.md` records the address scheme.

Backend tests cover the store, poller, admin handlers, and web routes (`go test ./...`, needs Docker).

Reviewed-on: #156
Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

backend/cover_test.go

@@ -32,7 +32,7 @@ func TestPublicCoverServesStoredBytesUnauthenticated(t *testing.T) {
 
 	// The wire URL is what a client actually requests, so the path under test
 	// is taken from it rather than rebuilt by hand.
-	wire := st.CoverWireURL(store.CoverAddress(sourceURL))
+	wire := st.CoverWireURL(store.CoverAddressForBytes([]byte("\x00webp-bytes")))
 	path, ok := strings.CutPrefix(wire, testCoverBaseURL)
 	if !ok {
 		t.Fatalf("wire URL %q is not on the public origin %q", wire, testCoverBaseURL)
@@ -57,7 +57,7 @@ func TestPublicCoverServesStoredBytesUnauthenticated(t *testing.T) {
 func TestPublicCoverRejectsUnknownAddress(t *testing.T) {
 	srv, _ := newWebTestServer(t, testConfig())
 	cases := map[string]string{
-		"unknown":   "/covers/" + store.CoverAddress("https://cdn.example/never-stored.jpg"),
+		"unknown":   "/covers/" + store.CoverAddressForBytes([]byte("never-stored")),
 		"malformed": "/covers/not-an-address",
 		"traversal": "/covers/../../etc/passwd",
 		"empty":     "/covers/",
@@ -86,7 +86,7 @@ func TestPublicCoverNeverEchoesNonImage(t *testing.T) {
 	}
 	// A legitimate row, then the content type flipped behind the store's back:
 	// the bytes exist at the address, so only the type is hostile.
-	address := store.CoverAddress(sourceURL)
+	address := store.CoverAddressForBytes([]byte("<script>"))
 	if err := st.SetSeriesCover("asura", "solo", sourceURL, []byte("<script>"), "image/png"); err != nil {
 		t.Fatalf("seed row: %v", err)
 	}
@@ -127,7 +127,7 @@ func TestListRendersAcquiredCover(t *testing.T) {
 	if rr.Code != http.StatusOK {
 		t.Fatalf("status = %d, want 200", rr.Code)
 	}
-	want := `src="` + testCoverBaseURL + "/covers/" + store.CoverAddress(sourceURL) + `"`
+	want := `src="` + testCoverBaseURL + "/covers/" + store.CoverAddressForBytes([]byte("\xff\xd8jpeg")) + `"`
 	if !strings.Contains(rr.Body.String(), want) {
 		t.Fatalf("rendered list does not contain %s", want)
 	}