gh_plot_reports corpus (4,299 plots) + concurrency + 4-GPU pool

CORPUS — 4,299 GH plot reports added (3,797 written + 502 from the
earlier slow run + 319 sitemap-listed URLs that 404'd as
discontinued). Combined with prior 760 varieties + 14 AgriPro
trials = 5,073 total chunks now indexed.

scrape/sources/gh_plot_reports.py — concurrency speedup:
- 4 worker threads (ThreadPoolExecutor), each with its own
  requests.Session for connection-pool efficiency.
- Shared class-level rate limiter (0.25 sec between ANY two
  requests across all threads). Net throughput ~4 req/sec —
  well below any rate-limit threshold a public site enforces.
- Diagnosis vs original 1 req/sec: GH had ZERO rate limiting,
  zero 429s, zero retries. The 1 sec self-throttle was just too
  conservative. Bench:
    1 worker  / 1.0 sec throttle:  ~0.4 plots/sec (190 min ETA)
    4 workers / 0.25 sec throttle: ~3 plots/sec  (~25 min actual)

rag/chunk.py — chunk size cap for nomic-embed-text's 2048-token
context window:
- Empirically tested: failure threshold is ~5,250 chars on
  numeric-heavy trial chunks (chars/token ratio 2.4 vs 3.5 for
  prose). Cap at 4,500 chars to be safely under at worst-case
  2.2 chars/token.
- Applied to BOTH variety and trial chunks. Marked truncated
  chunks with metadata.embed_truncated = True; FULL text stays
  in the on-disk .md for get_page to return verbatim.

.gitea/workflows/{refresh,image-only}.yml — OLLAMA_URL pool
restructured for the 4 GPU-pinned endpoints. Bench (50-chunk
batches on nomic-embed-text):

    .0.125:11434  (RTX 40-series)  242 embeds/sec  ← weight ×4
    .0.2:11436    (GPU-pinned)     108 embeds/sec  ← weight ×2
    .0.2:11435    (GPU-pinned)      72 embeds/sec  ← weight ×1
    localhost     (TITAN X)         37 embeds/sec  ← weight ×1

Weighting is done by listing the URL multiple times in
OLLAMA_URL since the embedder uses round-robin. .0.2:11434 is
explicitly EXCLUDED — it isn't pinned to a specific GPU.

Combined index rebuild for 5,073 chunks now finishes in ~3 min
(was 19+ on the single-endpoint pool).

Smoke tests:
✓ list_versions: 5,073 docs across 6 sources, 2 vendors, 6
  brands, 4 crops (corn 2711, soy 2016, silage 223, wheat 123).
✓ search_trials({crop=corn, state=IA, year=2024}): 3 IA 2024
  corn trials surfaced.
✓ search_trials("Phytophthora resistance soybean trial"): NK
  NK43-W1XFS top-1 in LA 2024 trial (cross-vendor result).
✓ search_trials("AP Iliad Idaho wheat"): AgriPro Washington/N
  Idaho 2025 trial surfaced.
✓ search_trials(product=DKC65-95): 3 corn trials containing
  that hybrid in IL/IA 2024.
✓ search_trials(product=NK1701): 3 corn trials in AR/MS 2024.
✓ Product filter correctly returns EMPTY for products that
  aren't in the corpus (DKC65-20 is a 2023 product; 2023 plots
  deferred). Anti-hallucination contract preserved.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

corpus/gh_plot_reports/ghpr-silage-oh-2025-2469647.md

@@ -0,0 +1,34 @@
+# Silage yield trial — Ohio, 2025
+
+- **Source:** Golden Harvest plot report (cross-vendor head-to-head)
+- **Crop:** Silage
+- **State:** Ohio (OH)
+- **Year:** 2025
+- **Plot ID:** 2469647
+- **Cooperator:** Lots-A-Leche Dairy
+- **Planted:** 2025-05-15
+- **Harvested:** 2025-10-02
+- **Population:** 32,000 seeds/acre
+- **Row width:** 30"
+- **URL:** https://www.goldenharvestseeds.com/silage/plot-report/oh/2025/2469647
+
+---
+## Results (top-down by rank)
+
+| Rank | Brand | Product | Traits | Ton/Acre | Milk Per Acre | Milk Per Ton | Beef Per Acre | Beef Per Ton |
+|---|---|---|---|---|---|---|---|---|
+| 1 | Channel | 193-42VT4P | - | 14.3 | 3362.0 | 14418.0 | 271.0 | 1000.0 |
+| 2 | Channel | 192-52SSP | - | 13.7 | 3528.0 | 14472.0 | 263.0 | 945.0 |
+| 3 | Enogen | E095D3-D | - | 13.4 | 3680.0 | 14838.0 | 283.0 | 959.0 |
+| 4 | Enogen | E107C1-D | - | 13.2 | 3299.0 | 13025.0 | 242.0 | 880.0 |
+| 5 | Enogen | E102K7-D | - | 13.1 | 3448.0 | 13566.0 | 253.0 | 893.0 |
+| 6 | Masters | Choice | MCT5856 | 12.7 | 3156.0 | 12056.0 | 229.0 | 834.0 |
+| 7 | Enogen | E094Z4-D | - | 12.6 | 2967.0 | 11209.0 | 202.0 | 790.0 |
+| 8 | Enogen | E112S5-D | - | 12.2 | 3044.0 | 11167.0 | 228.0 | 799.0 |
+| 8 | Rob-See-Co | RC4829-PCE | - | 12.2 | 3376.0 | 12319.0 | 245.0 | 817.0 |
+| 10 | Brevant | B02V87AM | - | 12.1 | 3265.0 | 11810.0 | 258.0 | 827.0 |
+| 11 | Enogen | E092W5-D | - | 12.0 | 3030.0 | 10911.0 | 228.0 | 785.0 |
+| 12 | Enogen | E111V7-D | - | 11.0 | 2847.0 | 9427.0 | 174.0 | 687.0 |
+| 13 | Channel | 198-99SSP | - | 10.7 | 3001.0 | 9593.0 | 244.0 | 714.0 |
+
+Top 5 by Ton/Acre: 193-42VT4P (Channel) 14.3, 192-52SSP (Channel) 13.7, E095D3-D (Enogen) 13.4, E107C1-D (Enogen) 13.2, E102K7-D (Enogen) 13.1.