Regenerate the matrix, the gesture book and the manual page for the duplicates review

docs/manual/index.html

@@ -110,6 +110,7 @@ th { color: var(--ink-dim); font-weight: 600; }
 <li><a href="#selecting-several">Selecting several</a></li>
 <li><a href="#collections">Collections</a></li>
 <li><a href="#bursts">Bursts</a></li>
+<li><a href="#duplicate-originals">Duplicate originals</a></li>
 </ul>
 </li>
 <li><a href="#developing-a-photograph">Developing a photograph</a>
@@ -207,6 +208,32 @@ the grid, and again to fold it back. A folded burst shows its earliest frame;
 to have it show another, open it and click the ring on the frame you want.</p>
 <p>With faces indexed, narrowing the grid to a person puts <code>Eyes open</code> beside
 their name on the filter bar, which leaves out the frames where they blinked.</p>
+<h3 id="duplicate-originals">Duplicate originals</h3>
+<p>A library put together by hand often holds the same RAW more than once — a
+dated folder, a <code>bck</code> folder beside it, a renamed copy another program
+exported. When the catalog finds files with the same camera, capture time
+and size in more than one place, <code>Duplicate originals</code> appears under the
+trash in the sidebar with how many there are; Settings offers the same page
+beside the other whole-library passes.</p>
+<p>The page lists each group with its picture and its paths. One copy is
+marked <code>Stays</code>: the one outside a folder named like a backup (<code>bck</code>,
+<code>backup</code>, <code>copy</code>, <code>old</code>…), then the one still named the way the camera named
+it (<code>_MG_4623</code>, <code>IMG_0001</code>, <code>DSC_0042</code>), then the one catalogued first. Tap
+another path to keep that copy instead, and untick <code>Include</code> to leave a
+group alone.</p>
+<p>Nothing moves until <code>Check</code> has read the first and last megabyte of every
+copy and each copy's sidecar. A group whose files differ, or whose copies
+carry two different edits, is marked skipped and says why — two edits of
+one frame are kept for virtual copies. What the check reads is kept, so a
+second visit costs nothing. The line under each group says what the copy
+that stays will gain: the highest rating, every keyword and collection, a
+flag or label the copies agree on, faces and the names on them, and the
+edit if only a copy had one. Where the copies disagree on a flag or a
+label, the one that stays keeps its own and the line says so.</p>
+<p><code>Move N copies to trash</code> does it, one group at a time: each group is merged
+and its spare copies moved together, or not at all. The copies go to the
+trash, not away — select them in the trash view and <code>Restore</code> puts them
+back where they were.</p>
 <h2 id="developing-a-photograph">Developing a photograph</h2>
 <p>Click a thumbnail to open it. The column on the right is every adjustment;
 the strip at its head narrows it to one group.</p>