docs: fill documentation gaps — MEMORY.md, secret sync, README generation

- MEMORY.md: update milestone count (32 milestones, 29 closed), fix pipe
  layer stats (14 pipelines, 230 steps), add key files (sem, lake, j2),
  add sem module and Databricks SDK sections with memory file pointers
- project_sem_module.md: new memory file for semantic coverage architecture
- project_databricks_sdk.md: new memory file for 18-service SDK integration
- README.md.j2: add README generation section with gen_readme.py usage,
  expand secret sync section with --list flag and description
- Regenerate README.md (12,320 tests)

README.md

@@ -330,9 +330,12 @@ status = mgr.get_run_status(run_id)
 
 ### Secret sync
 
+Push environment variables to Databricks secret scopes per `stack.toml [databricks.secrets]`:
+
 ```bash
 uv run python dev/scripts/sync_secrets.py --dry-run   # preview
 uv run python dev/scripts/sync_secrets.py              # push to Databricks
+uv run python dev/scripts/sync_secrets.py --list       # show current secrets
 ```
 
 ### Quality monitoring
@@ -451,6 +454,18 @@ uv run python -m pytest tests/ -m stub             # only stub status
 uv run python -m pytest tests/test_ast_coverage.py # structural invariants only
 ```
 
+### README generation
+
+`README.md` is generated from `README.md.j2` using live codebase data. Never edit `README.md` directly.
+
+```bash
+uv run python dev/scripts/gen_readme.py            # regenerate from template
+uv run python dev/scripts/gen_readme.py --check     # verify freshness (CI gate)
+uv run python dev/scripts/gen_readme.py --dry-run   # preview to stdout
+```
+
+Dynamic values pulled from: `compose.yml` (services), `pyproject.toml` (modules), pipeline registry (pipelines + steps), `pytest --collect-only` (test count), `api.auth.manifest` (credentials), `.gitea/workflows/` (workflow count).
+
 ## Project layout
 
 ```

README.md.j2

@@ -323,9 +323,12 @@ status = mgr.get_run_status(run_id)
 
 ### Secret sync
 
+Push environment variables to Databricks secret scopes per `stack.toml [databricks.secrets]`:
+
 ```bash
 uv run python dev/scripts/sync_secrets.py --dry-run   # preview
 uv run python dev/scripts/sync_secrets.py              # push to Databricks
+uv run python dev/scripts/sync_secrets.py --list       # show current secrets
 ```
 
 ### Quality monitoring
@@ -444,6 +447,18 @@ uv run python -m pytest tests/ -m stub             # only stub status
 uv run python -m pytest tests/test_ast_coverage.py # structural invariants only
 ```
 
+### README generation
+
+`README.md` is generated from `README.md.j2` using live codebase data. Never edit `README.md` directly.
+
+```bash
+uv run python dev/scripts/gen_readme.py            # regenerate from template
+uv run python dev/scripts/gen_readme.py --check     # verify freshness (CI gate)
+uv run python dev/scripts/gen_readme.py --dry-run   # preview to stdout
+```
+
+Dynamic values pulled from: `compose.yml` (services), `pyproject.toml` (modules), pipeline registry (pipelines + steps), `pytest --collect-only` (test count), `api.auth.manifest` (credentials), `.gitea/workflows/` (workflow count).
+
 ## Project layout
 
 ```