feat(datagen): add reserve grid positions and batch codes to lab config

- introduce reserve grid positions for QA witness pattern
- add batch codes to run entries in lab configuration
- update schedule with run start time and track interval
- enhance validation checks for run-batch mapping

.cursorrules

@@ -4,6 +4,16 @@
 
 Every commit message you generate MUST follow this convention exactly.
 
+### Source of truth (staged diff only)
+
+Base the message ONLY on `git diff --cached` (the index / staged changes).
+Do not use unstaged working-tree diffs, untracked files, recent commit
+messages, or chat context.
+
+- Mention only paths that appear in the staged diff.
+- If the index is empty, output exactly: `No staged changes`
+- Never mention a file (e.g. README.md) that is not in the staged diff.
+
 First line: type(scope): description
 - lowercase imperative English summary, under 72 characters, no trailing period
 - type is one of (closed list): feat fix perf refactor security docs ci chore test
@@ -14,7 +24,8 @@ Scope selection by changed files:
 - rules   = docs/rules/**
 - docs    = other prose docs (README.md, CLAUDE.md, docs/examples/**)
 - config  = configuration files (.gitignore, .cursorrules, editable YAML defaults)
-- datagen = lab-configuration and data-generation code (tasks 01-03)
+- datagen = lab-configuration and data-generation code (tasks 01-03:
+  make_lab_config.py, make_process_flow.py, generate_data.py)
 - convert = format converters: JSON-LD, SQLite, PostgreSQL, RDF (tasks 04-07)
 - bench   = benchmark queries, runner, extrapolation (tasks 08-10)
 - report  = reporting code and templates (task 11)