feat(v2): add LBA snapshot extractor and command

README.md

@@ -184,6 +184,7 @@ 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)
 
 Run extractor:
 
@@ -203,6 +204,12 @@ Dry-run validation (no file write):
 docker compose exec web python manage.py run_extractor public_json_snapshot --dry-run
 ```
 
+Run only the LBA extractor:
+
+```bash
+docker compose exec web python manage.py run_lba_extractor
+```
+
 Extractor environment variables:
 - `EXTRACTOR_USER_AGENT`
 - `EXTRACTOR_HTTP_TIMEOUT_SECONDS`
@@ -212,12 +219,29 @@ Extractor environment variables:
 - `EXTRACTOR_PUBLIC_JSON_URL`
 - `EXTRACTOR_PUBLIC_SOURCE_NAME`
 - `EXTRACTOR_INCLUDE_RAW_PAYLOAD`
+- `EXTRACTOR_LBA_STATS_URL`
+- `EXTRACTOR_LBA_SEASON_LABEL`
+- `EXTRACTOR_LBA_COMPETITION_EXTERNAL_ID`
+- `EXTRACTOR_LBA_COMPETITION_NAME`
 
 Notes:
 - extraction is intentionally low-frequency and uses retries conservatively
 - only public pages/endpoints should be targeted
 - emitted snapshots must match the same schema consumed by `import_snapshots`
 
+### LBA extractor assumptions and limitations (MVP)
+
+- `source_name` is fixed to `lba`
+- 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_LBA_COMPETITION_EXTERNAL_ID`
+  - `competition_name` from `EXTRACTOR_LBA_COMPETITION_NAME`
+- 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
+
 ## Migration and Superuser Commands
 
 ```bash