Split manifest into its own collection with TID rkeys

Each publish event now writes a fresh `lol.mlf.package/<tid>` record instead of clobbering a single `com.atproto.lexicon.schema/lol.mlf.package`. The schema definition and the manifest instance are different things in different collections, so they stop colliding when an mlf project dogfoods `lol.mlf.package` as a user lexicon. - mlf-atproto: new tid module (sortable base32 TID generator, CAS loop for monotonicity) - mlf-publish/manifest: drop the schema envelope; instance carries `$type = "lol.mlf.package"` and only instance fields - mlf-cli/publish: write manifest to `lol.mlf.package/<tid>` - mlf-cli/unpublish: list the manifest collection, pick the newest by TID, delete everything it lists + the full publish log