docs: fix stale references in PLAN, contracts, README

- README.md: update prompt count ~65 to ~70
- contracts/gitea-api.md: fix "Used in" annotations — POST
  branch_protections is Phase 7 only (not Phase 9), DELETE
  branch_protections is Phase 7 teardown only (Phase 9 uses PATCH),
  add missing used-in entries for GET commits and GET contents
- PLAN.md: replace stale UNRAID_GITEA_PORT/FEDORA_GITEA_PORT with
  macvlan vars, update REPO_N_NAME to REPO_NAMES, fix version defaults
  (1.23->1.25, 0.2.11->0.3.0), add missing setup/ files to tree,
  fix prompt table to match current ~70 variables, update require_vars
  lists to match actual scripts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -67,7 +67,7 @@ gitea-migration/
 ├── runners.conf.example      # Runner definitions template
 ├── lib/common.sh             # Shared functions + .env validators
 ├── setup/
-│   ├── configure_env.sh      # Interactive .env wizard (~65 prompts)
+│   ├── configure_env.sh      # Interactive .env wizard (~70 prompts)
 │   ├── configure_runners.sh  # Interactive runner definition wizard
 │   ├── macbook.sh            # Local prerequisites (brew packages)
 │   ├── unraid.sh             # Remote prerequisites (static binaries)