Add ProHarvest Seeds: 119 varieties + 161 cross-vendor plot reports

ProHarvest Seeds (independent Corn Belt brand, proharvestseeds.com) exposes
a public, no-auth WordPress REST API — cleaner ingestion than the HTML-only
independents. Two new sources:

- `proharvest` (variety identity, 119 row-crop varieties: 70 corn / 47 soy /
  2 wheat). Enumerated via /wp/v2/seed (seed-type taxonomy), agronomics
  parsed from each /seed/<slug>/ detail page into structured
  characteristics_groups so the ratings actually embed. Mixed scale: disease
  1-9 numeric (9=best, no flip), agronomic/general qualitative, soil HR/R.

- `proharvest_plots` (trials, data_type=trial, 161 plots, 2024+2025). Per-
  cooperator harvest reports via the custom /wp-json/proharvest/v1/plots?y=
  endpoint + PDF table extraction. Many are cross-vendor head-to-head
  (ProHarvest/Apex vs Pioneer/DEKALB/Becks/Channel/Wyffels). Handles ruled
  tables, unruled tables (text fallback; soy drops the Test-Wt column → 4 vs
  5 numerics), and off-template third-party reports (sanity-gated to verbatim
  so junk rows never ship). Image-only PDFs skipped + counted.

- rag/chunk.py: route proharvest_plots through the shared cross-vendor plot
  renderer (structured) / verbatim body (raw_text fallback).
- sources.json + lessons.md (rating-scales, trial-data).
- README/CLAUDE.md corpus inventory brought current (it had drifted: bayer
  931 not 475; ebberts/lg/agrigold were unlisted). New totals: 1,645 variety
  + 6,787 trial records.

robots.txt permissive (only search + /dealer-* disallowed); no ToS
automation clause. CI rebuilds the index from the committed corpus.

corpus/proharvest_plots/phpr-corn-2024-9519.json

@@ -0,0 +1,224 @@
+{
+  "source": "proharvest_plots",
+  "source_key": "phpr-corn-2024-9519",
+  "data_type": "trial",
+  "vendor": "ProHarvest Seeds",
+  "brand": "ProHarvest Seeds",
+  "crop": "corn",
+  "state": "IL",
+  "state_abbrev": "il",
+  "city": "Lexington",
+  "county": "McLean",
+  "year": 2024,
+  "plot_id": 9519,
+  "cooperator": "Hacker Farms",
+  "latitude": 40.6414237,
+  "longitude": -88.7834001,
+  "company_representative": "Doug Hanson",
+  "planted_date": "5/25/2024",
+  "harvested_date": "9/24/2024",
+  "previous_crop": "Soybeans",
+  "row_width": "30\"",
+  "population_seeds_per_acre": 34000,
+  "fungicide": "No",
+  "herbicide": null,
+  "insecticide": null,
+  "tillage": "Conventional",
+  "irrigation": null,
+  "results": [
+    {
+      "rank": 1,
+      "metrics": {
+        "Yield": 291.08,
+        "% H2O": 20.0,
+        "+/- Ave": 24.1
+      },
+      "brand": "Channel",
+      "product": "213-23",
+      "traits": "VT2ProRib"
+    },
+    {
+      "rank": 2,
+      "metrics": {
+        "Yield": 283.04,
+        "% H2O": 18.9,
+        "+/- Ave": 16.0
+      },
+      "brand": "ProHarvest",
+      "product": "84P78",
+      "traits": "TREC"
+    },
+    {
+      "rank": 3,
+      "metrics": {
+        "Yield": 280.74,
+        "% H2O": 19.7,
+        "+/- Ave": 13.8
+      },
+      "brand": "ProHarvest",
+      "product": "81P20",
+      "traits": "PCERib"
+    },
+    {
+      "rank": 4,
+      "metrics": {
+        "Yield": 279.19,
+        "% H2O": 22.0,
+        "+/- Ave": 12.2
+      },
+      "brand": "Golden Harvest",
+      "product": "15J91",
+      "traits": "V"
+    },
+    {
+      "rank": 5,
+      "metrics": {
+        "Yield": 276.1,
+        "% H2O": 17.7,
+        "+/- Ave": 9.1
+      },
+      "brand": "Channel",
+      "product": "209-25",
+      "traits": "SSPro Rib"
+    },
+    {
+      "rank": 6,
+      "metrics": {
+        "Yield": 274.02,
+        "% H2O": 20.2,
+        "+/- Ave": 7.0
+      },
+      "brand": "ProHarvest",
+      "product": "83P33",
+      "traits": "DGVT2PRib"
+    },
+    {
+      "rank": 7,
+      "metrics": {
+        "Yield": 273.33,
+        "% H2O": 20.4,
+        "+/- Ave": 6.3
+      },
+      "brand": "ProHarvest",
+      "product": "8360",
+      "traits": "VT2ProRib"
+    },
+    {
+      "rank": 8,
+      "metrics": {
+        "Yield": 273.18,
+        "% H2O": 20.3,
+        "+/- Ave": 6.2
+      },
+      "brand": "Golden Harvest",
+      "product": "GLV76",
+      "traits": "DGVT2PRib"
+    },
+    {
+      "rank": 9,
+      "metrics": {
+        "Yield": 271.9,
+        "% H2O": 17.1,
+        "+/- Ave": 4.9
+      },
+      "brand": "Channel",
+      "product": "211-70",
+      "traits": "TRERib"
+    },
+    {
+      "rank": 10,
+      "metrics": {
+        "Yield": 269.02,
+        "% H2O": 18.7,
+        "+/- Ave": 2.0
+      },
+      "brand": "Golden Harvest",
+      "product": "G10L16",
+      "traits": "DV"
+    },
+    {
+      "rank": 11,
+      "metrics": {
+        "Yield": 268.69,
+        "% H2O": 18.8,
+        "+/- Ave": 1.7
+      },
+      "brand": "ProHarvest",
+      "product": "82P79",
+      "traits": "VT2ProRib"
+    },
+    {
+      "rank": 12,
+      "metrics": {
+        "Yield": 267.05,
+        "% H2O": 19.6,
+        "+/- Ave": 0.1
+      },
+      "brand": "ProHarvest",
+      "product": "81P65",
+      "traits": "V"
+    },
+    {
+      "rank": 13,
+      "metrics": {
+        "Yield": 259.03,
+        "% H2O": 19.7,
+        "+/- Ave": -8.0
+      },
+      "brand": "Channel",
+      "product": "217-01",
+      "traits": "VT2ProRib"
+    },
+    {
+      "rank": 14,
+      "metrics": {
+        "Yield": 258.64,
+        "% H2O": 18.4,
+        "+/- Ave": -8.3
+      },
+      "brand": "Channel",
+      "product": "211-57",
+      "traits": "SSRib"
+    },
+    {
+      "rank": 15,
+      "metrics": {
+        "Yield": 245.37,
+        "% H2O": 19.8,
+        "+/- Ave": -21.6
+      },
+      "brand": "Channel",
+      "product": "215-42",
+      "traits": "SSProRib"
+    },
+    {
+      "rank": 16,
+      "metrics": {
+        "Yield": 239.75,
+        "% H2O": 19.5,
+        "+/- Ave": -27.2
+      },
+      "brand": "Channel",
+      "product": "214-40",
+      "traits": "VT4PRib"
+    },
+    {
+      "rank": 17,
+      "metrics": {
+        "Yield": 228.75,
+        "% H2O": 17.8,
+        "+/- Ave": -38.2
+      },
+      "brand": "Golden Harvest",
+      "product": "G051186",
+      "traits": "DV"
+    }
+  ],
+  "n_results": 17,
+  "raw_text": false,
+  "source_urls": [
+    "https://proharvestseeds.com/wp-content/uploads/2024/11/Corn-Hacker-Farms-Lexington-IL-61753.pdf"
+  ],
+  "fetched_at": "2026-06-05T00:58:16.029487+00:00",
+  "scraper_version": "0.1.0"
+}