Event-sourced storage as the foundation — current state is always a projection

LOGOS must be built on an event-sourced storage model at the
foundation. This is an architectural requirement, not a feature.
Every capability that makes LOGOS meaningfully different from a
conventional forum — time travel, full history, audit, revert,
AI training corpus integrity, import provenance — is a natural
consequence of this foundation. Without it, those capabilities
are bolted on at best.

Why It's Needed

Conventional forum software stores current state. When something
changes, the previous state is overwritten. History, if available
at all, is a secondary concern implemented as an afterthought.
Talkyard is a clear example — revision numbers are tracked
internally but history is not accessible, because history was
never the primary model.

LOGOS treats knowledge accumulation as a first-class design
requirement. That requires a storage model where accumulation is
the default behavior, not an add-on.

The Requirement

Every action in LOGOS is an immutable timestamped event appended
to an event log. Nothing is overwritten. Nothing is deleted —
only superseded by subsequent events. Current state of any entity
— a topic, a post, a category, a user's understanding — is always
derived by projecting forward from the events that shaped it.

This means:

• Time travel is possible — reconstruct state at any point
  in history
• Audit is complete — every change has an author, timestamp,
  and reason
• Revert is safe — restoring previous state is a new event,
  not a destructive operation
• Import preserves provenance — imported conversations carry
  their original event timestamps and remain traceable to their
  source
• AI training corpus is honest — the corpus reflects actual
  history, not a sanitized current snapshot

The GIT Analogy

GIT manages code this way. Every commit is an immutable event.
Current state is the result of applying all commits in sequence.
You can check out any commit and see the full state of the
codebase at that moment. Branches, merges, and reverts are all
events — nothing is lost.

LOGOS applies this model to knowledge rather than code. The
commit history of a requirement topic is as important as the
current state of it. The sequence of understanding matters,
not just the destination.

Relationship to Other Requirements

This is the foundation requirement. The following are capabilities
that fall out of it naturally:

• Event-sourced editing with full revision history
• Full edit history visible on all content types
• Chat import as provenance infrastructure
• AI training corpus integrity

Acceptance

All user actions — creating, editing, moving, tagging, importing
— produce immutable events in the event log. No action overwrites
a previous state. Current state of any entity can be derived by
replaying its events from any point in time. The event log is
exportable in full.

Sources

• LOGOS → Requirements → Event-sourced editing with full revision history (capability that depends on this foundation)
• LOGOS → Talkyard Limitations → Wiki edit history is not accessible (concrete example of what's missing without this foundation)