Incremental pipeline (pipeline_incremental.c):
- Disk-based delta re-indexing: classifies files by mtime+size vs stored
hashes, deletes changed nodes (edges cascade), re-parses only changed
files, merges into existing DB via cbm_gbuf_merge_into_store
- pipeline.c auto-routes: existing DB with hashes -> incremental, else full
- Full pipeline persists file hashes after dump for next incremental run
- No-op when nothing changed (watcher polls every 5-60s, 99% skip)
- 4 tests: noop, changed file, deleted file, new file added
ADR hints (ported from Go):
- index_repository: adr_present + adr_hint when no ADR exists
- get_graph_schema: adr_present + adr_hint per project
- manage_adr GET: adr_hint with creation instructions when no ADR