feat: expose row-level can_edit/can_delete on select *

Compute per-row editability and deletability from a table's row-level
security policies and return them as synthetic columns so clients can
hide edit/delete affordances for rows the user cannot change.

- Introspect pg_policies and relrowsecurity at schema-cache load and
  combine the UPDATE/DELETE USING qualifiers per table (permissive OR,
  restrictive AND).
- Store the combined qualifiers on Table and inject can_edit/can_delete
  as computed select fields when expanding `select *`, only for
  RLS-enabled tables with a matching policy (COALESCE'd to a boolean).
- Keep the computed columns out of the OpenAPI spec so they are not
  rendered as regular fields.
- Add a cfExpression field to CoercibleField to carry raw SQL
  expressions through the planner to SqlFragment.

test/io/__snapshots__/test_cli/test_schema_cache_snapshot[dbTables].yaml

@@ -7,6 +7,42 @@
     tableIsView: false
     tableName: authors_only
     tablePKCols: []
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
+    tableSchema: public
+    tableUniqueCols: []
+    tableUpdatable: true
+
+- - qiName: no_rls_items
+    qiSchema: public
+  - tableColumns:
+      id:
+        colDefault: null
+        colDescription: null
+        colEnum: []
+        colMaxLen: null
+        colName: id
+        colNominalType: integer
+        colNullable: false
+        colType: integer
+      name:
+        colDefault: null
+        colDescription: null
+        colEnum: []
+        colMaxLen: null
+        colName: name
+        colNominalType: text
+        colNullable: true
+        colType: text
+    tableDeletable: true
+    tableDescription: null
+    tableInsertable: true
+    tableIsView: false
+    tableName: no_rls_items
+    tablePKCols:
+    - id
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -39,6 +75,53 @@
     tableName: cats
     tablePKCols:
     - id
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
+    tableSchema: public
+    tableUniqueCols: []
+    tableUpdatable: true
+
+- - qiName: rls_items
+    qiSchema: public
+  - tableColumns:
+      account_id:
+        colDefault: null
+        colDescription: null
+        colEnum: []
+        colMaxLen: null
+        colName: account_id
+        colNominalType: bigint
+        colNullable: true
+        colType: bigint
+      id:
+        colDefault: null
+        colDescription: null
+        colEnum: []
+        colMaxLen: null
+        colName: id
+        colNominalType: integer
+        colNullable: false
+        colType: integer
+      name:
+        colDefault: null
+        colDescription: null
+        colEnum: []
+        colMaxLen: null
+        colName: name
+        colNominalType: text
+        colNullable: true
+        colType: text
+    tableDeletable: true
+    tableDescription: null
+    tableInsertable: true
+    tableIsView: false
+    tableName: rls_items
+    tablePKCols:
+    - id
+    tableRlsDeleteQual: COALESCE(((((current_setting('request.jwt.claims'::text, true))::json
+      ->> 'account_id'::text))::bigint = account_id), false)
+    tableRlsEditQual: COALESCE(((((current_setting('request.jwt.claims'::text, true))::json
+      ->> 'account_id'::text))::bigint = account_id), false)
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -70,6 +153,8 @@
     tableIsView: true
     tableName: items_w_isolation_level
     tablePKCols: []
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -102,6 +187,8 @@
     tableName: directors
     tablePKCols:
     - id
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -115,6 +202,8 @@
     tableIsView: false
     tableName: projects
     tablePKCols: []
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -128,6 +217,8 @@
     tableIsView: true
     tableName: infinite_recursion
     tablePKCols: []
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: false
@@ -187,6 +278,8 @@
     tableName: awards
     tablePKCols:
     - id
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -228,6 +321,8 @@
     tableName: films
     tablePKCols:
     - id
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true
@@ -250,6 +345,8 @@
     tableIsView: false
     tableName: items
     tablePKCols: []
+    tableRlsDeleteQual: null
+    tableRlsEditQual: null
     tableSchema: public
     tableUniqueCols: []
     tableUpdatable: true