code cleanup; listed invariants; enforce duration minutes invariant across edits; renamed notes to tasks everywhere

dev-notes/data invariants.md

@@ -0,0 +1,20 @@
+# Data Invariants
+
+This file contains notes on invariants which must be upheld across running toru commands for the vault and configuration.
+
+# tasks::Task
+- name cannot be purely numeric
+- ID must be unique
+
+# tasks::Duration
+- minutes should be less than 60
+
+# state::State (in state.toml)
+- the `next_id` should always be greater than the ID of any task within the vault
+
+# index::Index (in state.toml)
+- the index of name to ID map should be correct given the names and IDs of all vaults
+
+# graph::Graph (in state.toml)
+- should always have dependencies the same as specified in each task file
+- no circular dependencies should be allowed to exist between tasks (and by extension should not exist in the state file)