feat(v2): add BCL snapshot extractor and command

README.md

@@ -185,6 +185,7 @@ Extractor pipeline:
 Built-in extractor in this phase:
 - `public_json_snapshot` (generic JSON feed extractor for MVP usage)
 - `lba` (Lega Basket Serie A MVP extractor)
+- `bcl` (Basketball Champions League MVP extractor)
 
 Run extractor:
 
@@ -210,6 +211,12 @@ Run only the LBA extractor:
 docker compose exec web python manage.py run_lba_extractor
 ```
 
+Run only the BCL extractor:
+
+```bash
+docker compose exec web python manage.py run_bcl_extractor
+```
+
 Extractor environment variables:
 - `EXTRACTOR_USER_AGENT`
 - `EXTRACTOR_HTTP_TIMEOUT_SECONDS`
@@ -223,6 +230,10 @@ Extractor environment variables:
 - `EXTRACTOR_LBA_SEASON_LABEL`
 - `EXTRACTOR_LBA_COMPETITION_EXTERNAL_ID`
 - `EXTRACTOR_LBA_COMPETITION_NAME`
+- `EXTRACTOR_BCL_STATS_URL`
+- `EXTRACTOR_BCL_SEASON_LABEL`
+- `EXTRACTOR_BCL_COMPETITION_EXTERNAL_ID`
+- `EXTRACTOR_BCL_COMPETITION_NAME`
 
 Notes:
 - extraction is intentionally low-frequency and uses retries conservatively
@@ -239,7 +250,18 @@ Notes:
 - season is configured by `EXTRACTOR_LBA_SEASON_LABEL`
 - parser supports payload keys: `records`, `data`, `players`, `items`
 - normalization supports nested `player` and `team` objects with common stat aliases (`gp/mpg/ppg/rpg/apg/spg/bpg/tov`)
-- no BCL support in this task
+- no live HTTP calls in tests; tests use fixtures/mocked responses only
+
+### BCL extractor assumptions and limitations (MVP)
+
+- `source_name` is fixed to `bcl`
+- the extractor expects one stable public JSON payload that includes player/team/stat rows
+- competition is configured by environment and emitted as:
+  - `competition_external_id` from `EXTRACTOR_BCL_COMPETITION_EXTERNAL_ID`
+  - `competition_name` from `EXTRACTOR_BCL_COMPETITION_NAME`
+- season is configured by `EXTRACTOR_BCL_SEASON_LABEL`
+- parser supports payload keys: `records`, `data`, `players`, `items`
+- normalization supports nested `player` and `team` objects with common stat aliases (`gp/mpg/ppg/rpg/apg/spg/bpg/tov`)
 - no live HTTP calls in tests; tests use fixtures/mocked responses only
 
 ## Migration and Superuser Commands