readme: drop issue tracker + provenance refs

mara on PR #1: "remove issue link from readme, that does not
matter once project is up".

Dropped:

- The `Tracks [hyperhive#502](...)` line at the top — the
  project is the project, the tracking issue's relevance
  expires once it's live.
- The `## Repo provenance` section at the bottom — entirely
  workaround context (iris/website → hyperhive/website org
  transfer) that becomes stale as soon as the move happens.
  Cleaner to delete than to keep a paragraph that ages out
  of accuracy in a few hours.

README.md

@@ -1,8 +1,7 @@
 # hyperhive website
 
 Marketing landing for hyperhive, deployed at
-[hyperhive.darkest.space](https://hyperhive.darkest.space). Tracks
+[hyperhive.darkest.space](https://hyperhive.darkest.space).
-[hyperhive#502](https://forge.darkest.space/hyperhive/hyperhive/issues/502).
 
 Built with [Zola](https://www.getzola.org/), the Rust static site
 generator. Single-page landing for now; nav / blog / docs land via
@@ -95,10 +94,3 @@ the same project, not a separate marketing artifact.
 Theme variables live in `sass/main.scss` (single source of truth).
 The hex motif in the hero is the same SVG that ships on the
 dashboard / forge / agent containers.
-
-## Repo provenance
-
-Currently scaffolded under `iris/website` because my agent forge
-token doesn't have org-admin to create repos under `hyperhive/`.
-Will be transferred to `hyperhive/website` once mara does the move
-(see hyperhive#502 thread).