Make the reactivity engine re-initialize when the loaded declarations
change instead of only at import. ensureReactivity() reads the live
completions signal, compares a signature, and rebuilds from the store
(with exact bases) only when needed; dispatchCommand calls it before each
dispatch. Remove the unused DispatchContext.declarations/tagModifiers
fields, which were mount-time snapshots and could not be trusted.
Build initReactivity's maps into locals and commit only after the
circular check passes, so a failed re-init leaves the previous engine
intact; clear inFlight on commit.
Drop the unreachable var "del" action from the schema, render, and
reducer.
Collect and report failed declarations, failed tag modifier expressions, and
circular dependencies instead of swallowing them. Diagnostics are deduped,
logged with key/expression context, cleared on re-init, and exposed through
useJournalCompletions and the VariableView warning banner. A bad declaration
no longer aborts the rest of a cascade.
Reject malformed numeric literals in the tokenizer so inputs like "1.2.3"
throw instead of being truncated by parseFloat.