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-2024-2419568.md

@@ -0,0 +1,40 @@
+# Soybean yield trial — South Dakota, 2024
+
+- **Source:** Golden Harvest plot report (cross-vendor head-to-head)
+- **Crop:** Soybean
+- **State:** South Dakota (SD)
+- **Year:** 2024
+- **Plot ID:** 2419568
+- **Cooperator:** Lake Area Ag
+- **Planted:** 2024-05-19
+- **Harvested:** 2024-10-14
+- **Population:** 130,000 seeds/acre
+- **Row width:** 30"
+- **URL:** https://www.goldenharvestseeds.com/soybean/plot-report/sd/2024/2419568
+
+---
+## Results (top-down by rank)
+
+| Rank | Brand | Product | Traits | Yield | %MST | Test Weight | Gross Revenue |
+|---|---|---|---|---|---|---|---|
+| 1 | Stine | 11EC02 | - | 66.2 | 9.1 | - | $695.10 |
+| 2 | Jacobsen | J1710E3 | - | 64.3 | 10.1 | - | $675.15 |
+| 3 | Jacobsen | J1520E3 | - | 63.8 | 9.9 | - | $669.90 |
+| 4 | Stine | 15EE32 | - | 62.5 | 10.1 | - | $656.25 |
+| 5 | Stine | 13EG23 | - | 60.4 | 9.7 | - | $634.20 |
+| 6 | Stine | 11EH06 | - | 60.2 | 10.0 | - | $632.10 |
+| 7 | Stine | 13EH62 | - | 59.5 | 9.3 | - | $624.75 |
+| 8 | LG Seeds | LGS1832E3 | - | 58.9 | 10.1 | - | $618.45 |
+| 8 | Jacobsen | J1930E3 | - | 58.9 | 12.0 | - | $618.45 |
+| 10 | Stine | 14EE21 | - | 58.2 | 10.3 | - | $611.10 |
+| 11 | Golden Harvest | GH1495E3 | Enlist E3 ® | 57.5 | 9.6 | - | $603.75 |
+| 12 | LG Seeds | LGS1043E3 | - | 56.5 | 9.2 | - | $593.25 |
+| 13 | Golden Harvest | GH1194E3 | Enlist E3 ® | 55.1 | 9.6 | - | $578.55 |
+| 14 | Stine | 08EC32 | - | 54.1 | 9.2 | - | $568.05 |
+| 14 | LG Seeds | LGS1206E3 | - | 54.1 | 9.2 | - | $568.05 |
+| 16 | Jacobsen | J1250E3 | - | 53.5 | 9.2 | - | $561.75 |
+| 17 | LG Seeds | LGS0830E3 | - | 52.4 | 9.0 | - | $550.20 |
+| 18 | LG Seeds | LGS1551E3 | - | 52.1 | 9.6 | - | $547.05 |
+| 19 | Jacobsen | J1643E3 | - | 49.5 | 10.0 | - | $519.75 |
+
+Top 5 by Yield: 11EC02 (Stine) 66.2, J1710E3 (Jacobsen) 64.3, J1520E3 (Jacobsen) 63.8, 15EE32 (Stine) 62.5, 13EG23 (Stine) 60.4.