Adds Commit, Sync, SyncTo, Read, Files, Diff, Tip, ExtractTo, Config methods on *Agent that take/return only primitives or types defined in this package. No *libfossil.* in any new signature, so consumers can perform the bones-style code-artifact operations without importing libfossil.

New types: RevID (opaque commit handle), FileToCommit, CommitOpts, SyncOpts, SyncResult — all libfossil-free.

Internal SQLite tuning (SetMaxOpenConns(1) + busy_timeout=30s) is now applied on every agent boot. libfossil PRAGMAs are per-connection so the single-conn cap is what makes them stick — concurrent-write safety that any production agent needs.

Repo() and NotifyRepo() stay as escape hatches for sim/test and advanced consumers; doc comments updated to recommend the new methods.

Closes #103 check-in: 3309ec60d5 user: [email protected] tags: trunk