historic_sql_patterns

# Historic SQL Patterns Use this skill when the WorkUnit raw file is a `patterns-input/part-0001.json` style shard from the `historic-sql` adapter. Older staged bundles may still provide root `patterns-input.json`; when that is the WorkUnit raw file, read it the same way. ## Required Workflow 1. Read the WorkUnit notes first. 2. Find the single pattern input file listed under the WorkUnit `rawFiles` section. 3. Call `read_raw_file` for that exact raw file path. 4. Identify recurring analytical intents that span at least two tables and have repeated usage signal. 5. Emit one `pattern` evidence object per durable cross-table intent by calling `emit_historic_sql_evidence`. 6. Stop after all pattern evidence has been emitted. Every join column mentioned in pattern descriptions must be verified via entity_details for both sides of the join. ## 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, chec...