Answer the review: HYG's own last-resort name is a designation too

Junie: a HYG star that fell all the way through the ETL's naming chain --
no proper name, Bayer, Flamsteed, HD, Gliese or HIP -- is called "HYG <id>",
and with `source: 'hyg'` the predicate was looking for a lower-case "hyg "
prefix and calling it named. None in the current catalogue, but the path is
in `tools/etl/fetchStars.ts` and a refresh could walk it.

Fixed in the table rather than in the predicate: `hyg: 'HYG'` next to
`gaia: 'Gaia DR3'`, so the encoder, the decoder and the predicate all read the
one rule. The sourceless case reads the same entry instead of repeating it.

npm test 609/609, build and ETL typecheck clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014fcUfL82nvyh9VebX1Fz6w

src/app/shared/models/star-catalog.spec.ts

@@ -139,5 +139,10 @@ describe('star catalogue provenance and derived names', () => {
     // 32-bit row id can equal — so it is the prefix that decides, not a round trip through the id.
     expect(isDesignation({ ...MIXED[1], name: 'Gaia DR3 5853498713190525696' })).toBe(true);
     expect(isDesignation({ ...MIXED[1], name: 'Proxima Centauri' })).toBe(false);
+    // HYG's own last resort, once every designation it knows has come up empty. Upper case,
+    // whatever case the source id is in.
+    expect(isDesignation({ ...MIXED[0], name: 'HYG 5' })).toBe(true);
+    expect(isDesignation({ ...MIXED[0], source: undefined, name: 'HYG 5' })).toBe(true);
+    expect(isDesignation({ ...MIXED[0], name: 'HD 48915' })).toBe(false);
   });
 });