Adds a consolidated invariant layer (INV-1..INV-5) so that context-isolated
implementers (e.g. parallel isolated subagents holding only one subsystem
slice) cannot violate global rules they cannot see in their slice.
- INV-1: session-DB state columns written only by event projection, with an
authoritative table→event map and explicit heartbeat/ui_state exemptions.
This is the rule the O2 finding violated; centralizing it prevents recurrence.
- INV-2: cross-DB writes use outbox + single writer.
- INV-3: side effects only through ToolRegistry → PermissionEngine.
- INV-4: one-way import/dependency direction.
- INV-5: EventBus is transport, never a source of truth.
Each affected subsystem chapter (§5/§7/§8/§9/§11) now opens with an
"Applicable invariants (§18.6)" pointer so the constraint travels with the
slice. Pure documentation consolidation of already-frozen rules; zero change
to contracts, events, schema, or runtime semantics.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
b7091dbd1e