Timeline

* feat: CreateOpts.ProjectCode — accept explicit project-code on Create

Downstream EdgeSync coordinates a shared project-code across sibling Fossil repos created on different machines so its NATS sync subject ("<prefix>.<project-code>.sync") matches across leaves. Today every Create generates a fresh project-code, so commits never propagate.

Add CreateOpts.ProjectCode: empty preserves current behavior; non-empty must be 40-char lowercase hex (^[0-9a-f]{40}$) — the same format generated project-codes use. Validation runs at the top of libfossil.Create before any disk I/O, so invalid input cannot leave a half-written file behind. Server-code stays auto-generated.

Threaded through repo.Create / repo.CreateWithEnv / db.SeedConfig. SeedConfig validates as defense-in-depth (public package, multiple callers possible).

Clone accepting ProjectCode is out of scope; will follow separately if EdgeSync needs it.

* test: round-trip explicit ProjectCode through fossil rebuild

Asserts that vanilla `fossil` (2.28) accepts a Go-side repo created with an explicit ProjectCode, and that `fossil sql` reads back the same value we set. Closes the gap where the existing TestCreate_FossilValidation only covered the generated-project-code path. check-in: 6b66ea6b2d user: [email protected] tags: trunk, v0.6.1