The hub.Config.ProjectCode and hub.Config.SeedFromUpstream fields landed in #157 but were unreachable from the `edgesync hub serve` CLI. Wires them through and fixes a latent auth bug in seedFromUpstream that prevented it from cloning against the standard nobody-caps=gio deployment.

Changes: * cli/hub_serve.go — adds --project-code (40-char lowercase hex, format pre-validated for a friendlier error than libfossil's) and --seed-from-upstream (http(s) URL of upstream hub xfer endpoint). * hub/clone.go — drop bootstrapUser from the clone CloneOpts. Passing a local-creation user as the upstream-auth identity caused libfossil's clone to send a login card for a user the upstream had never heard of ("authentication failed"). Anonymous clone falls through to the upstream's "nobody" caps, matching the typical NobodyCaps:"gio" deploy. * hub/cross_leaf_test.go — adds TestCrossLeaf_SeedFromUpstream_PropagatesCommit covering the seed-then-sync path end-to-end (clone over HTTP, leaf-link, observe A→B commit propagation via NATS). leaf check-in: 001f82d3d2 user: 41898282+github-actions[bot]@users.noreply.github.com tags: trunk, feat/cli-project-code-and-seed-from-upstream