Add 30k Space-Track catalog and benchmark results

Space-Track USSPACECOM catalog: 29,784 objects from full GP query.
Benchmark shows SP-GiST index reaches parity with seqscan at 30k:
  - Delta: +1.6ms (14k) -> +0.9ms (20k) -> +0.0ms (30k)
  - Planner voluntarily chooses Index Only Scan at this scale
  - Zero heap fetches (all data served from index pages)
  - 75.9% candidate pruning on 2h/10deg query

Archive includes TLEs from Space-Track, TLE API, and SatNOGS.

bench/benchmark_results_30k.txt

@@ -0,0 +1,115 @@
+pg_orrery v0.7.0 SP-GiST Benchmark — 30k Space-Track Catalog
+=============================================================
+Date: 2026-02-17
+Catalog: Space-Track USSPACECOM full catalog (29,784 objects)
+Host: Linux 6.16.5-arch1-1, PostgreSQL 17
+Branch: phase/spgist-orbital-trie
+
+Catalog Composition:
+  LEO (<128 min):          25,641  (86.1%)
+  MEO (128-720 min):        1,801  ( 6.0%)
+  GEO/HEO (720-1500 min):  2,253  ( 7.6%)
+  Super-GEO (>1500 min):      89  ( 0.3%)
+
+Index Build:
+  SP-GiST: 46.7 ms, 4,816 kB
+  GiST:    65.8 ms, 5,856 kB
+  Table:              4,760 kB
+
+==============================================================
+TIMING RESULTS (best of 3 runs, ms)
+==============================================================
+
+Query Pattern                | Seqscan | SP-GiST | Delta
+-----------------------------|---------|---------|-------
+2h window, Eagle ID, 10 deg  |  5.19   |  5.22   | +0.03
+6h window, Eagle ID, 10 deg  |  5.34   |  6.34   | +1.00
+24h window, Eagle ID, 10 deg |  5.42   |  6.68   | +1.26
+2h window, Eagle ID, 30 deg  |  5.54   |  5.64   | +0.10
+2h window, equatorial, 10deg |  5.26   |  5.59   | +0.33
+
+==============================================================
+PRUNING RESULTS
+==============================================================
+
+Query Pattern                | Candidates | % Pass | % Pruned
+-----------------------------|------------|--------|---------
+2h window, Eagle ID, 10 deg  |    7,188   |  24.1% |   75.9%
+6h window, Eagle ID, 10 deg  |   12,373   |  41.5% |   58.5%
+24h window, Eagle ID, 10 deg |   26,971   |  90.6% |    9.4%
+2h window, Eagle ID, 30 deg  |    5,232   |  17.6% |   82.4%
+2h window, equatorial, 10deg |    4,670   |  15.7% |   84.3%
+
+==============================================================
+BUFFER I/O COMPARISON (2h Eagle 10deg)
+==============================================================
+
+Method      | Pages Read | Heap Fetches | Scan Type
+------------|------------|--------------|------------------
+Seqscan     |    595     |     n/a      | Seq Scan
+SP-GiST     |  2,396     |       0      | Index Only Scan
+
+SP-GiST reads 4.0x more pages than seqscan (2,396 vs 595).
+But uses Index Only Scan with zero heap fetches.
+
+==============================================================
+CONSISTENCY CHECK
+==============================================================
+
+False negatives: 0  (index never misses a seqscan result)
+False positives: 0  (index never returns extra results)
+Seqscan count:   7,188
+SP-GiST count:   7,188
+
+==============================================================
+SCALING TREND (2h Eagle 10deg, best-of-3)
+==============================================================
+
+Catalog Size | Seqscan | SP-GiST | Delta  | SP-GiST Pages | Seq Pages
+-------------|---------|---------|--------|---------------|----------
+14,376       |  4.5 ms |  6.1 ms | +1.6ms |      888      |    291
+20,597       |  3.8 ms |  4.7 ms | +0.9ms |    (IOOS)     |   (est)
+29,784       |  5.2 ms |  5.2 ms | +0.0ms |    2,396      |    595
+
+The delta is converging toward zero. At 30k the SP-GiST index is
+essentially tied with seqscan on the 2h/10deg query. For queries
+with fewer survivors (30deg elevation, equatorial observer), the
+index is within 0.1-0.3ms.
+
+==============================================================
+PLANNER BEHAVIOR
+==============================================================
+
+PostgreSQL's query planner CHOOSES the SP-GiST index by default
+at 30k (without any enable_seqscan=off forcing). The planner's
+cost model prefers the Index Only Scan.
+
+EXPLAIN output (default settings):
+  Index Only Scan using bench_spgist on bench_catalog
+    Index Cond: (tle &? ...)
+    Heap Fetches: 0
+    Buffers: shared hit=2396
+    Execution Time: 7.246 ms (with planning)
+
+==============================================================
+NOTES
+==============================================================
+
+1. At 30k objects, the planner voluntarily chooses SP-GiST over
+   seqscan. This is the crossover point where the index becomes
+   the planner's preferred strategy.
+
+2. The Index Only Scan with zero heap fetches means the index
+   contains all information needed — no table access required.
+
+3. The 75.9% pruning rate on the 2h window means only 7,188 of
+   29,784 satellites need SGP4 propagation. This avoids ~22,596
+   unnecessary SGP4 calls in the predict_passes() pipeline.
+
+4. The equatorial observer (84.3% pruned) and high-elevation
+   (82.4% pruned) queries show the strongest filtering because
+   the altitude and RAAN filters are most aggressive there.
+
+5. The 24h window only prunes 9.4% because the RAAN filter
+   self-disables for full Earth rotations, leaving only the
+   altitude and inclination filters active.