Constants & Tunables (cheat sheet)

Name	Value	Where
`MANIFEST_DIR`	`__manifest`	`db/manifest/layout.rs`
Commit graph dir	`_graph_commits.lance`	`db/commit_graph.rs`
Run registry dir (legacy, removed MR-771)	`_graph_runs.lance`	inert post-v0.4.0; reclaimed by MR-770
Run branch prefix (legacy, removed MR-771)	`__run__`	filtered by `is_internal_run_branch` defense-in-depth
Schema apply lock	`__schema_apply_lock__`	`db/mod.rs`
Manifest publisher retry budget	`PUBLISHER_RETRY_BUDGET = 5`	`db/manifest/publisher.rs`
Internal manifest schema version	`INTERNAL_MANIFEST_SCHEMA_VERSION = 2`	`db/manifest/migrations.rs`
Merge stage batch	`MERGE_STAGE_BATCH_ROWS = 8192`	`exec/merge.rs`
Maintenance concurrency	`OMNIGRAPH_MAINTENANCE_CONCURRENCY=8`	`db/omnigraph/optimize.rs`
Graph index cache size	`8` (LRU)	`runtime_cache.rs`
Default body limit	`1 MB`	`omnigraph-server/lib.rs`
Ingest body limit	`32 MB`	`omnigraph-server/lib.rs`
Engine embed model	`gemini-embedding-2-preview`	`omnigraph/embedding.rs`
Compiler embed model	`text-embedding-3-small`	`omnigraph-compiler/embedding.rs`
Embed timeout	`30 000 ms`	both clients
Embed retries	`4`	both clients
Embed retry backoff	`200 ms`	both clients
LANCE memory pool default	`1 GB` (raised in v0.3.0)	runtime