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-wi-2025-2470205.md

@@ -0,0 +1,33 @@
+# Silage yield trial — Wisconsin, 2025
+
+- **Source:** Golden Harvest plot report (cross-vendor head-to-head)
+- **Crop:** Silage
+- **State:** Wisconsin (WI)
+- **Year:** 2025
+- **Plot ID:** 2470205
+- **Cooperator:** Mervin Burkholder
+- **Planted:** 2025-05-14
+- **Harvested:** 2025-10-07
+- **Population:** 28,000 seeds/acre
+- **Row width:** 30"
+- **URL:** https://www.goldenharvestseeds.com/silage/plot-report/wi/2025/2470205
+
+---
+## Results (top-down by rank)
+
+| Rank | Brand | Product | Traits | Ton/Acre | Milk Per Acre | Milk Per Ton | Beef Per Acre | Beef Per Ton |
+|---|---|---|---|---|---|---|---|---|
+| 1 | Mustang | Seeds | 32P91 VT2P | 29.9 | 2884.0 | 25869.0 | - | - |
+| 2 | Renk | Seed | RK4545AV | 29.3 | 2968.0 | 26056.0 | - | - |
+| 3 | Renk | Seed | RK571PCE | 28.4 | 2970.0 | 25334.0 | - | - |
+| 3 | ProHarvest | Seeds | 6650PCE | 28.4 | 2980.0 | 25390.0 | - | - |
+| 5 | ProHarvest | Seeds | 68P78PCE | 26.4 | 3180.0 | 25154.0 | - | - |
+| 6 | Mustang | Seeds | 28U88 SS | 26.3 | 2910.0 | 22960.0 | - | - |
+| 7 | Mustang | Seeds | 22Z90 VT2P | 25.7 | 2861.0 | 22056.0 | - | - |
+| 8 | Renk | Seed | RK583PCE | 24.7 | 3026.0 | 22453.0 | - | - |
+| 9 | Mustang | Seeds | 22K88 VT2P | 24.5 | 2695.0 | 19795.0 | - | - |
+| 10 | NK | NK9231-AA | - | 23.8 | 2970.0 | 21233.0 | - | - |
+| 11 | LG Seeds | LG48C87VT2P | - | 23.1 | 2670.0 | 18521.0 | - | - |
+| 12 | NK | NK9044-AA | - | 20.9 | 2877.0 | 18065.0 | - | - |
+
+Top 5 by Ton/Acre: Seeds (Mustang) 29.9, Seed (Renk) 29.3, Seed (Renk) 28.4, Seeds (ProHarvest) 28.4, Seeds (ProHarvest) 26.4.