Update the newly added note files and remove references to ignored files

hqew/015-sql-front-end-and-logical-planning.md

@@ -47,15 +47,15 @@ A clean front end gives the engine:
 
 ## The pipeline in the companion repo
 
-Relevant modules:
+Relevant implementation areas:
 
-- `tmp/how-query-engines-work/sql/src/main/kotlin/SqlTokenizer.kt`
-- `tmp/how-query-engines-work/sql/src/main/kotlin/Tokens.kt`
-- `tmp/how-query-engines-work/sql/src/main/kotlin/SqlParser.kt`
-- `tmp/how-query-engines-work/sql/src/main/kotlin/Expressions.kt`
-- `tmp/how-query-engines-work/sql/src/main/kotlin/SqlPlanner.kt`
-- `tmp/how-query-engines-work/logical-plan/src/main/kotlin/LogicalPlan.kt`
-- `tmp/how-query-engines-work/logical-plan/src/main/kotlin/Expressions.kt`
+- SQL tokenization
+- SQL tokens and keywords
+- SQL parsing
+- SQL AST expressions
+- SQL-to-logical planning
+- logical plan interfaces
+- logical expressions
 
 Conceptually:
 
@@ -368,4 +368,5 @@ It is what allows:
 
 ## Changelog
 
+* **Apr 7, 2026** -- Removed references to ignored local `tmp/` paths.
 * **Apr 7, 2026** -- Added a dedicated note on SQL tokenization, parsing, AST structure, and logical planning.

hqew/016-physical-plans-and-operators.md

@@ -31,16 +31,16 @@ That makes the logical-to-physical boundary easy to study.
 
 ## The physical planning pipeline
 
-Relevant modules:
+Relevant implementation areas:
 
-- `tmp/how-query-engines-work/query-planner/src/main/kotlin/QueryPlanner.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/PhysicalPlan.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/ScanExec.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/SelectionExec.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/ProjectionExec.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/HashAggregateExec.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/HashJoinExec.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/LimitExec.kt`
+- query planning from logical to physical operators
+- the physical-plan interface
+- scan execution
+- selection execution
+- projection execution
+- hash aggregation
+- hash join
+- limit execution
 
 Conceptually:
 
@@ -375,4 +375,5 @@ So this note should be read as a physical-plan primer, not as the full space of
 
 ## Changelog
 
+* **Apr 7, 2026** -- Removed references to ignored local `tmp/` paths.
 * **Apr 7, 2026** -- Added a dedicated note on physical planning, executable operators, and batch-oriented runtime behavior.

hqew/017-expressions-types-and-nullability.md

@@ -49,18 +49,17 @@ So expressions are not side details. They are a large part of the engine's real
 
 ## The two-layer model
 
-Relevant modules:
+Relevant implementation areas:
 
-- `tmp/how-query-engines-work/logical-plan/src/main/kotlin/LogicalExpr.kt`
-- `tmp/how-query-engines-work/logical-plan/src/main/kotlin/Expressions.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/expressions/Expressions.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/expressions/BinaryExpression.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/expressions/CastExpression.kt`
-- `tmp/how-query-engines-work/physical-plan/src/main/kotlin/expressions/AggregateExpression.kt`
-- `tmp/how-query-engines-work/datatypes/src/main/kotlin/Schema.kt`
-- `tmp/how-query-engines-work/datatypes/src/main/kotlin/ColumnVector.kt`
-- `tmp/how-query-engines-work/datatypes/src/main/kotlin/RecordBatch.kt`
-- `tmp/how-query-engines-work/datatypes/src/main/kotlin/ArrowTypes.kt`
+- logical-expression interfaces and helpers
+- physical-expression interfaces
+- binary-expression evaluation
+- cast evaluation
+- aggregate-expression interfaces
+- schema and field definitions
+- column-vector abstractions
+- record batches
+- Arrow-based type definitions
 
 The key distinction is:
 
@@ -381,4 +380,5 @@ That is why "choosing a type system" appears so early in the book. It affects mu
 
 ## Changelog
 
+* **Apr 7, 2026** -- Removed references to ignored local `tmp/` paths.
 * **Apr 7, 2026** -- Added a dedicated note on expressions, Arrow-based types, coercion, aggregates, and null handling.