Add pedigree lookup and ancestry tree page

New 🌳 Pedigree view: enter a dog's ISO chip or SKK registration number
and see its ancestry rendered as a tree. SKK has no public API, so the
server drives SKK Hunddata like a browser: it resolves the input to an
internal hundid via the Hund_sok.aspx/HundData page-method, renders 7
generations per pedigree page, parses the rowspan grid into ahnentafel
positions, and follows each generation's leaves deeper by reading their
hundid out of the __doPostBack response viewstate.

A lookup returns the first 7 generations immediately and crawls deeper in
the background; the client polls and fills the tree in as ancestors
arrive. Finished trees are cached per dog in a new pedigree_cache table
(pedigrees don't change), so a dog is crawled once and repeats are instant.
The endpoints sit behind auth like the rest of /api/*, and the crawl is
kept polite (warmed session, delay between requests, one coalesced job per
dog, hard caps).

src/changelog.json

@@ -1,4 +1,5 @@
 [
+  { "date": "2026-07-26", "text": "New 🌳 Pedigree page: look up any dog in SKK Hunddata by chip or registration number and explore its ancestry as a tree — the first generations show at once, then the line fills in further back as it's traced" },
   { "date": "2026-07-24", "text": "The age counter reads \"16 weeks (3 months and 3 weeks) old\" so weeks and months line up; past 4 months it drops the weeks and shows just months (e.g. \"5 months and 2 weeks old\")" },
   { "date": "2026-07-17", "text": "The Sleep trend chart follows the selected day — pick a past day to see its full curve against the day before and the average leading up to it" },
   { "date": "2026-07-15", "text": "The Sleep trend y-axis is stretched above 10h, giving the hours around the sleep goal most of the chart" },