crewai: add agromatrix and plant-intel role packs with updated team config

docs/agromatrix-plant-intel-contract.md

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+# AgroMatrix Plant Intel Contract (Skeleton)
+
+## Purpose
+`agromatrix_plant_intel` is an internal CrewAI profile for Stepan (AgroMatrix orchestrator).
+It is used for plant/crop identification and normalization when confidence matters.
+
+## Call Path
+1. User asks Stepan.
+2. Stepan remains final speaker.
+3. When query matches plant-intel intent, CrewAI profile `plant_intel` is selected.
+4. Subteam runs:
+   - `plant_identifier`
+   - `taxonomy_validator`
+   - `agrovoc_normalizer`
+5. Synthesis returns compact evidence package to Stepan.
+
+## Tool Adapters
+- `nature_id_identify`
+  - input: `image_url`, `top_k?`
+  - output: local/open-source candidates
+  - note: requires self-hosted endpoint `NATURE_ID_URL`
+- `plantnet_lookup`
+  - input: `query?`, `image_url?`, `organ?`, `top_k?`
+  - output: candidate taxa + score
+  - note: if `PLANTNET_API_KEY` missing, fallback chain is `nature_id_identify` -> `gbif_species_lookup`
+- `gbif_species_lookup`
+  - input: `query`, `limit?`
+  - output: accepted taxa/rank/status
+- `agrovoc_lookup`
+  - input: `query`, `lang?`, `limit?`
+  - output: canonical AGROVOC concepts
+
+## Response Contract (to Stepan)
+- `probable_taxon`
+- `confidence` (`low|medium|high` + reason)
+- `alternatives` (up to 3)
+- `sources` (actual tools used)
+- `next_photos_required` (1-3 concrete instructions)
+
+## Safety
+- No categorical claim with weak evidence.
+- If sources conflict, confidence is downgraded.
+- Final user answer remains concise by default.