Move internal notes out of the visitor path

Delete fork-added working artifacts: the session handoff, backlog, memlab
run report, self-hosting UX report, full-suite failure log, CI recovery
plan, consolidated source reconciliation and the first vertical-slice
plan. Move the dated upstream candidate audit and reconciliation report,
the runtime assurance plan, the migration status log and the
upstream-next-three specs into docs/internal/ with a README stating they
are history. Kept in place: README, attribution and security files,
AGENTS.md, configuration and reference docs, the qualification plan,
runbooks and protocols, and docs/agents (a contract test reads them).
Updated the README migration status link and cross-references in the
moved reports. No upstream-authored files were touched.

Author: ngallodev

BACKLOG.md

@@ -332,7 +332,7 @@ See [`SECURITY.md`](SECURITY.md) and [`docs/SECURITY-DISCLOSURE.md`](docs/SECURI
 
 ## Migration documents
 
-- [`docs/CLI_MIGRATION_STATUS.md`](docs/CLI_MIGRATION_STATUS.md) — current port and qualification status.
+- [`docs/internal/CLI_MIGRATION_STATUS.md`](docs/internal/CLI_MIGRATION_STATUS.md) — current port and qualification status.
 - [`docs/RELEASE_QUALIFICATION_PLAN.md`](docs/RELEASE_QUALIFICATION_PLAN.md) — build, platform, benchmark, and release gates.
 - [`docs/CLI_ONLY_MIGRATION_PLAN.md`](docs/CLI_ONLY_MIGRATION_PLAN.md) — historical rationale and scope of the MCP removal.