feat(ephemeris): bump libephemeris to 3.0.0rc8 + regenerate all baselines at extended tier

Upgrade the ephemeris backend pin from rc6 to rc8 and regenerate every golden
baseline (svg, reports, positions, subjects, aspects, house-systems, sidereal-modes,
perspectives, returns, composite, ephemeris-ranges) against rc8 at the extended
(DE441) tier.

rc8 data-quality changes that drove the baseline drift (all Swiss-Ephemeris validated):
- Sidereal ayanamsas (0-46) re-derived from published author (value,epoch) statements
  via Vondrak Method-B; Lahiri re-anchored to the IAE J2000 constant; Siddhantic
  mean-Sun ayanamsas rebuilt. These deliberately diverge from Swiss Eph on sidereal
  positions (sub-arcsec for Fagan/Bradley & Krishnamurti; 10-32" for the Babylonian/
  DeLuce/Usha/Khul/Bhasin modes; up to ~5.5' for Yukteshwar's book value) — documented
  in libephemeris docs/comparison/intentional-divergences.md.
- Lunar apsides (Interpolated Lilith/Perigee) re-anchored to actual DE440 apsis passages.
- Tropical planets and ASC/MC now match Swiss Eph exactly (rc7's ASC was 0.036" off);
  this also resolves the chart-SVG ASC drift.

pyproject: pin LIBEPHEMERIS_PRECISION=extended as the default for every regenerate:*
poe task (regenerate:all, svg, reports, positions, aspects, configurations) so baselines
regenerate on-disk with the full-range kernel and BCE/ancient subjects (year 100 AD,
500 BC) resolve instead of falling back — no manual env prefix needed. Report fixtures
regenerated at extended now satisfy both --tier=base and --tier=extended under rc8.

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

Author: g-battaglia

pyproject.toml

@@ -46,7 +46,7 @@ classifiers = [
 requires-python = ">=3.12"
 dependencies = [
     # TODO before tagging 6.0.0: bump the floor to the stable 3.0.0 once released.
-    "libephemeris==3.0.0rc6",
+    "libephemeris==3.0.0rc8",
     "pydantic>=2.5",
     "svg-polish>=1.0.0",
     "requests-cache>=1.2.1",
@@ -257,6 +257,9 @@ help = "Test Python snippets in markdown files"
 sequence = ["regenerate:svg:base", "regenerate:svg:extended", "regenerate:svg:modern"]
 help = "Regenerate all SVG chart baselines (tests/data/svg/)"
 
+[tool.poe.tasks."regenerate:svg".env]
+LIBEPHEMERIS_PRECISION = "extended"
+
 [tool.poe.tasks."regenerate:svg:base"]
 cmd = "python scripts/regenerate_test_charts.py"
 
@@ -270,6 +273,9 @@ cmd = "python scripts/generate_modern_baselines.py"
 sequence = ["regenerate:reports:snapshots", "regenerate:reports:output"]
 help = "Regenerate all report golden files (tests/fixtures/)"
 
+[tool.poe.tasks."regenerate:reports".env]
+LIBEPHEMERIS_PRECISION = "extended"
+
 [tool.poe.tasks."regenerate:reports:snapshots"]
 cmd = "python scripts/regenerate_report_snapshots.py"
 
@@ -280,10 +286,16 @@ cmd = "python scripts/regenerate_test_output.py"
 cmd = "python scripts/regenerate_all.py --positions --subjects"
 help = "Regenerate expected positions and subjects (tests/data/expected_positions.py, expected_astrological_subjects.py)"
 
+[tool.poe.tasks."regenerate:positions".env]
+LIBEPHEMERIS_PRECISION = "extended"
+
 [tool.poe.tasks."regenerate:aspects"]
 sequence = ["regenerate:aspects:natal", "regenerate:aspects:synastry"]
 help = "Regenerate all expected aspects (tests/data/expected_*_aspects.py)"
 
+[tool.poe.tasks."regenerate:aspects".env]
+LIBEPHEMERIS_PRECISION = "extended"
+
 [tool.poe.tasks."regenerate:aspects:natal"]
 cmd = "python scripts/regenerate_expected_aspects.py"
 
@@ -294,9 +306,17 @@ cmd = "python scripts/regenerate_synastry_aspects.py"
 cmd = "python scripts/regenerate_all.py --configurations"
 help = "Regenerate all configuration-specific fixtures (house-systems, sidereal-modes, perspectives, returns, composite, ephemeris, arabic-parts)"
 
+[tool.poe.tasks."regenerate:configurations".env]
+LIBEPHEMERIS_PRECISION = "extended"
+
 [tool.poe.tasks."regenerate:all"]
 sequence = ["regenerate:svg", "regenerate:reports", "regenerate:positions", "regenerate:aspects", "regenerate:configurations"]
 help = "Regenerate all golden standards"
+# Baselines must regenerate at the extended (DE441) tier so ancient/BCE subjects
+# (year 100 AD, etc.) resolve on-disk instead of falling back, and so the long-range
+# subjects aren't silently dropped (41 vs 32). Per memory baseline-regeneration-tier.
+[tool.poe.tasks."regenerate:all".env]
+LIBEPHEMERIS_PRECISION = "extended"
 
 [tool.poe.tasks.benchmark]
 cmd = "python scripts/benchmark.py"