feat: add historic sql evidence skills

packages/context/skills/historic_sql_patterns/SKILL.md

@@ -0,0 +1,57 @@
+---
+name: historic_sql_patterns
+description: Identify recurring cross-table historic-SQL analytical intents and emit typed pattern evidence for deterministic wiki projection.
+callers: [memory_agent]
+---
+
+# Historic SQL Patterns
+
+Use this skill when the WorkUnit raw file is `patterns-input.json` from the `historic-sql` adapter.
+
+## Required Workflow
+
+1. Read the WorkUnit notes first.
+2. Call `read_raw_file` for `patterns-input.json`.
+3. Identify recurring analytical intents that span at least two tables and have repeated usage signal.
+4. Emit one `pattern` evidence object per durable cross-table intent by calling `emit_historic_sql_evidence`.
+5. Stop after all pattern evidence has been emitted.
+
+## Evidence Shape
+
+Each call to `emit_historic_sql_evidence` must use this shape:
+
+```json
+{
+  "kind": "pattern",
+  "rawPath": "patterns-input.json",
+  "pattern": {
+    "slug": "order-lifecycle-analysis",
+    "title": "Order Lifecycle Analysis",
+    "narrative": "Analysts compare order statuses with customer segments to understand lifecycle movement.",
+    "definitionSql": "select o.status, count(*) from public.orders o join public.customers c on c.id = o.customer_id group by o.status",
+    "tablesInvolved": ["public.orders", "public.customers"],
+    "slRefs": ["orders", "customers"],
+    "constituentTemplateIds": ["pg:1", "pg:2"]
+  }
+}
+```
+
+The `pattern` object must match `patternOutputSchema`; multiple calls together must form `patternsArraySchema`.
+
+## Pattern Selection Rules
+
+- Prefer patterns that involve two or more tables.
+- Prefer templates with `executionsBucket` at least `10-100` and `distinctUsersBucket` above solo usage.
+- Merge templates into one pattern only when the business intent is the same.
+- Use a stable kebab-case slug based on intent, not a template id.
+- Set `definitionSql` to the clearest representative SQL from a constituent template.
+- Set `slRefs` to source names when the source name is obvious from table names; omit uncertain refs rather than guessing.
+
+## Boundaries
+
+- Do not call wiki_write.
+- Do not call sl_write_source.
+- Do not call sl_edit_source.
+- Do not call context_candidate_write.
+- Do not create single-table pattern pages.
+- Do not copy credentials, tokens, user emails, or unredacted literals into evidence.