docs(readme): semantic_query is a search_graph parameter; team artifact is opt-in (#1297)

README.md

@@ -199,7 +199,7 @@ The install script placed beside the binary is **reported, not deleted** — uni
 - **Cypher-like queries**: `MATCH (f:Function)-[:CALLS]->(g) WHERE f.name = 'main' RETURN g.name`
 
 ### Search
-- **Semantic search** (`semantic_query`): vector search across the entire graph, powered by bundled Nomic `nomic-embed-code` embeddings (40K tokens, 768d int8) compiled into the binary — no API key, no Ollama, no Docker. 11-signal combined scoring (TF-IDF, RRI, API/Type/Decorator signatures, AST profiles, data flow, Halstead-lite, MinHash, module proximity, graph diffusion).
+- **Semantic search** (the `semantic_query` parameter of `search_graph`, not a separate tool): vector search across the entire graph, powered by bundled Nomic `nomic-embed-code` embeddings (40K tokens, 768d int8) compiled into the binary — no API key, no Ollama, no Docker. 11-signal combined scoring (TF-IDF, RRI, API/Type/Decorator signatures, AST profiles, data flow, Halstead-lite, MinHash, module proximity, graph diffusion).
 - **BM25 full-text search** via SQLite FTS5 with `cbm_camel_split` tokenizer (camelCase / snake_case aware)
 - **Structural search** (`search_graph`): regex name patterns, label filters, min/max degree, file scoping
 - **Code search** (`search_code`): graph-augmented grep over indexed files only
@@ -243,12 +243,12 @@ The install script placed beside the binary is **reported, not deleted** — uni
 
 Commit a single compressed file to your repo and your teammates skip the reindex.
 
-`.codebase-memory/graph.db.zst` is a zstd-compressed snapshot of the knowledge graph that lives next to your source. When you index, the artifact is written or refreshed; when a teammate clones the repo and runs `codebase-memory-mcp` for the first time, the artifact is decompressed and incremental indexing fills in their local diff.
+`.codebase-memory/graph.db.zst` is a zstd-compressed snapshot of the knowledge graph that lives next to your source. The artifact is opt-in: `index_repository` writes it only with `persistence: true` (the default is `false`), and once it exists later indexes refresh it; when a teammate clones the repo and runs `codebase-memory-mcp` for the first time, the artifact is decompressed and incremental indexing fills in their local diff.
 
 - **Format**: SQLite database, indexes stripped, `VACUUM INTO` compacted, then zstd 1.5.7 compressed (8–13:1 ratio typical)
 - **Two tiers**:
-  - **Best** (`zstd -9` + index strip + `VACUUM INTO`) — written on explicit `index_repository`
-  - **Fast** (`zstd -3`) — written by the watcher for low-latency incremental updates
+  - **Best** (`zstd -9` + index strip + `VACUUM INTO`) — written by `index_repository` with `persistence: true`
+  - **Fast** (`zstd -3`) — refreshes an existing artifact on every other index (including the watcher's low-latency incremental updates)
 - **Bootstrap**: when no local DB exists but the artifact is present, `index_repository` imports the artifact first, then runs incremental indexing — avoiding the full reindex cost
 - **No merge pain**: a `.codebase-memory/.gitattributes` line with `merge=ours` is auto-created on first export, so concurrent edits don't produce conflicts on the binary artifact
 - **Commit it deliberately**: the artifact is rewritten on every index, including the watcher's Fast tier, and git stores each rewrite as a full new blob. Committing every refresh is what turns a 20 MB file into gigabytes of history — one team reached ~6 GB across ~350 commits of this single path. Pick a cadence (a release, a milestone, a nightly job) rather than committing every save.