Add the profile page, and publish it as an embeddable panel

Developed in a separate session; committed here alongside the calendar work
that shares this repository's migration journal.

A person can now see their own Plex link, their Watch Now slots and their watch
history at /profile. The same panel is published in two further forms so that
accounts.sticknife.com on charon can carry it as one section of a wider
sticknife profile, next to the other services' sections.

  - watch_history (0024) records what has been played, keyed on the Plex
    history id so a re-sync cannot duplicate a row. Partial unique index,
    because that id is null for anything entered by hand.
  - plex_accounts.is_server_owner (0025) marks the one account whose viewing
    the server files under local account 1 rather than under its plex.tv id.
  - The embed carries its own layout, origin allowlist and a frame-height
    reporter, so the host page can size it without guessing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/lib/catalog.ts

@@ -153,6 +153,21 @@ function imageUrl(path?: string | null) {
   return path ? `${TMDB_IMAGE_BASE_URL}${path}` : null;
 }
 
+/**
+ * A usable poster URL from whatever media_items.poster_path happens to hold.
+ *
+ * Two writers disagree about that column. The metadata refresh stores TMDB's
+ * bare path (`/abc.jpg`, 2,802 rows) and the catalog board stores the absolute
+ * URL it had already built (1 row). Both forms are in the table right now, so
+ * anything rendering a stored poster has to cope with both -- and anything
+ * handing one to ANOTHER SERVICE has to resolve it, because a bare TMDB path
+ * means nothing on accounts.sticknife.com.
+ */
+export function posterUrlFromStored(path?: string | null) {
+  if (!path) return null;
+  return /^https?:\/\//.test(path) ? path : imageUrl(path);
+}
+
 function backdropUrl(path?: string | null) {
   return path ? `${TMDB_BACKDROP_BASE_URL}${path}` : null;
 }