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-soybeans-sd-2025-2466413.md

@@ -0,0 +1,41 @@
+# Soybean yield trial — South Dakota, 2025
+
+- **Source:** Golden Harvest plot report (cross-vendor head-to-head)
+- **Crop:** Soybean
+- **State:** South Dakota (SD)
+- **Year:** 2025
+- **Plot ID:** 2466413
+- **Cooperator:** Chs Dakota Plains Ag
+- **Planted:** 2025-05-06
+- **Harvested:** 2025-10-01
+- **Population:** 145,000 seeds/acre
+- **Row width:** 30"
+- **URL:** https://www.goldenharvestseeds.com/soybean/plot-report/sd/2025/2466413
+
+---
+## Results (top-down by rank)
+
+| Rank | Brand | Product | Traits | Yield | %MST | Test Weight | Gross Revenue |
+|---|---|---|---|---|---|---|---|
+| 1 | NK | NK11-A4E3 | Enlist E3 ® | 61.9 | 9.2 | - | $649.95 |
+| 2 | Allegiant | Allegiant | 09F16N XF | 60.0 | 9.2 | - | $630.00 |
+| 3 | Asgrow | AG06XF3 | - | 59.5 | 9.5 | - | $624.75 |
+| 4 | Asgrow | AG09XF3 | - | 59.2 | 9.5 | - | $621.60 |
+| 5 | Asgrow | AG10XF4 | - | 58.9 | 9.1 | - | $618.45 |
+| 6 | Allegiant | Allegiant | 07F36N XF | 58.7 | 9.2 | - | $616.35 |
+| 6 | Asgrow | AG12XF4 | - | 58.7 | 9.2 | - | $616.35 |
+| 8 | Brevant | B095EE | - | 57.1 | 9.4 | - | $599.55 |
+| 9 | NK | NK09-V2E3 | Enlist E3 ® | 56.4 | 9.3 | - | $592.20 |
+| 10 | Asgrow | AG07XF4 | - | 55.4 | 9.2 | - | $581.70 |
+| 11 | NK | NK07-G5E3 | Enlist E3 ® | 54.8 | 9.4 | - | $575.40 |
+| 12 | Attain | Attain | 08A6N | 54.1 | 9.4 | - | $568.05 |
+| 13 | NK | NK08-Z4E3 | Enlist E3 ® | 53.5 | 9.3 | - | $561.75 |
+| 14 | Attain | Attain | 09A5N | 53.4 | 9.6 | - | $560.70 |
+| 15 | Brevant | B135EE | - | 53.3 | 10.4 | - | $559.65 |
+| 16 | NK | NK14-U5E3 | Enlist E3 ® | 52.8 | 10.9 | - | $554.40 |
+| 17 | Attain | Attain | 13A5N | 52.4 | 9.9 | - | $550.20 |
+| 18 | Attain | Attain | 14A2N | 49.5 | 10.9 | - | $519.75 |
+| 19 | Allegiant | Allegiant | 14F35N XF | 48.6 | 10.2 | - | $510.30 |
+| 20 | Brevant | B144EE | - | 44.2 | 11.4 | - | $464.10 |
+
+Top 5 by Yield: NK11-A4E3 (NK) 61.9, Allegiant (Allegiant) 60.0, AG06XF3 (Asgrow) 59.5, AG09XF3 (Asgrow) 59.2, AG10XF4 (Asgrow) 58.9.