chore: purge retired git.tx1138.com registry host from the codebase

The tx1138 Gitea was retired as a release server 2026-06-13 and its registry
frontend is fully dead (500 on every /v2 manifest read, observed 2026-07-10).
Nothing may reference it anymore:

- registry.rs: no longer a default registry, no longer force-enabled on
  load; saved configs are stripped of it on load (same one-time migration
  treatment as the decommissioned Hetzner mirror), with a regression test.
- image_policy.rs: removed from TRUSTED_REGISTRIES — refs through the dead
  host are now refused at the pull site (rejection test added).
- api/handler: dropped the legacy catalog-proxy fallback URL.
- .gitmodules: indeedhub submodule repointed to the OVH Gitea.
- scripts, image-recipe, app-catalog data, neode-ui strings, docs, and all
  test fixtures repointed to 146.59.87.168:3000 (or neutral example hosts).
- image-versions.sh: ARCHY_REGISTRY_FALLBACK emptied (guarded consumers
  skip it); reconcile-containers.sh candidate guard hardened.

The only remaining occurrences of the host string are the strip/reject
enforcement paths and their regression tests — the code that guarantees it
is never used again.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/self-update.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-# Self-update: pull latest code from git.tx1138.com and apply
+# Self-update: pull latest code from the OVH Gitea (146.59.87.168:3000) and apply
 # Designed to run on installed Archipelago nodes (as archipelago user)
 #
 # Usage:
@@ -8,7 +8,7 @@
 #   ./self-update.sh --force      # Apply even if already up to date
 #
 # The script:
-#   1. Pulls latest code from origin (git.tx1138.com)
+#   1. Pulls latest code from origin (146.59.87.168:3000)
 #   2. Builds the Rust backend (release mode)
 #   3. Builds the Vue frontend (production mode)
 #   4. Installs the new binary and web UI
@@ -69,7 +69,7 @@ done
 # Ensure repo exists
 if [ ! -d "$REPO_DIR/.git" ]; then
     err "Repo not found at $REPO_DIR"
-    err "Clone it first: git clone https://git.tx1138.com/lfg2025/archy ~/archy"
+    err "Clone it first: git clone http://146.59.87.168:3000/lfg2025/archy ~/archy"
     exit 1
 fi