historic_sql_table_digest

# Historic SQL Table Digest Use this skill when the WorkUnit raw file is one `tables/<schema>.<name>.json` file from the `historic-sql` adapter. ## Required Workflow 1. Read the WorkUnit notes first. 2. Call `read_raw_file` for the single `tables/<schema>.<name>.json` raw file. 3. Read `manifest.json` only if the table JSON omits the dialect or the WorkUnit notes are unclear. 4. Produce one concise usage narrative for this table from the staged table JSON. 5. Call `emit_historic_sql_evidence` exactly once with `kind: "table_usage"`. 6. Stop after the evidence tool succeeds. ## Identifier Verification Protocol Before writing a wiki page or SL source on any topic: 1. `discover_data({query: "<topic>"})` - see what wikis, SL sources, and raw tables already exist. Prefer updating existing pages over creating new ones. Before emitting any `schema.table` or `schema.table.column` into a wiki body, SL source, `tables:` frontmatter, `sl_refs`, or `emit_unmapped_fallback`: 2. `entity_details({connectionId, targets: [{display: "<identifier>"}]})` - confirm the identifier resolves; inspect native types, FK/PK, and sampleValues. 3. For literal values from the source, such as status codes or plan tiers, check whether they appear in `entity_details` sampleValues for the relevant column. If sampleValues is short or the sample may have missed real values, run a `sql_execution` probe with the same warehouse connection id: `sql_execution({connectionId, sql: "SELECT D...