Document finance_saa memory integration state

[mdheller]

Summary

Adds docs/status/finance-saa-memory-integration.md to record the current merged state of the finance_saa + memoryd work.

What the document covers

• current merged runtime state
• relevant merged PRs
• runtime surfaces now present
• validation/test surfaces now present
• known limitations
• cross-repo ownership map
• recommended next implementation phase
• completion definition for Phase 1
• follow-on integration phases

Why this matters

The finance/memory work moved quickly across several PRs and direct mainline updates. This status document provides a stable repo-local checkpoint before the next implementation phase: typed artifact APIs in memoryd and deterministic finance session reconstruction.

Scope

Documentation only. No runtime code changes.

[mdheller]

Operational note: the status document from this PR has now been landed directly onto main as commit 5a8301b4382a08dc9fa012cdd69ceaa478e5ed7d.

This PR is therefore superseded by the direct mainline additive commit. The implementation it proposed is already present on main at:

• docs/status/finance-saa-memory-integration.md

I cannot close this PR from the current connector surface, but it should be treated as superseded/complete.