D28 — Removal of raw/, mcp/, source_ingest, scrub, exporter (June 2026)

Decision. The raw/ and mcp/ directories are removed from the KB structure. The internal/scrub and internal/exporter packages are deleted. The source_ingest MCP tool and the --exporter flag in main.go are removed. The configurator abandons mcp/wiki.yaml in favor of CLI flags (--name, --transport, --url, --auth, --token-env). Rationale. The complexity of source_ingest (copy into raw/, secret scrubbing, webhook exporter, content-hash provenance) did not hold up cost/benefit-wise for the small-to-medium KBs that are the primary target. The direct write cycle via concept_write is simpler, verifiable, and composable with existing LLM tools. The PII quality guarantee moves to the LLM-as-judge quality-gate at the ingest checkpoint. mcp/wiki.yaml added a file that every user had to keep aligned with their CLI flags — the defaults in DefaultConfig() cover the common case without extra files.