docs: update KB from architecture review

[ivan-aksamentov]

docs/kb-architecture-audit -> fix/tree-output-augur-parity

Create:

• kb/issues/: add source-verified architecture findings

Update:

• kb/: reconcile current architecture, algorithms, and ticket readiness

Delete:

• kb/tickets/: remove tickets based on stale structures or unresolved ownership decisions

An AI architecture review found cross-cutting design defects whose KB coverage was broad, stale, or absent.

Reconcile the findings against current source, replace umbrella tracking with atomic issues, and remove implementation tickets whose premises no longer hold.

Work items

• Record architecture findings with evidence, constraints, and validation requirements [src]
• Reconcile command, partition, mutation, output, and reroot tracking with current source [src]
• Retain tickets only when their implementation direction is ready [src]