ci: drop the Gitea mirror-sync nudge

Superseded: the Hanzo GitHub App pushes a webhook, so the forge tracks GitHub
without a per-repo workflow. This file called git.hanzo.ai/api/v1/.../mirror-sync
— a Gitea API for a system we no longer drive — and would sit inert in every repo.

One mechanism, in one place, instead of ~350 copies of a cron.

.github/workflows/sync.yml

@@ -1,60 +0,0 @@
-name: Sync to git.hanzo.ai
-# DIRECTION: this repo on git.hanzo.ai is a PULL MIRROR fetching github.com/hanzoai/xorm.
-# GitHub is UPSTREAM, git.hanzo.ai is DOWNSTREAM. The giveaway is what this file does:
-# mirror-sync tells Gitea to PULL, which only makes sense if GitHub is the source.
-#
-# This matters beyond labeling: a pull mirror force-updates its refs from upstream on
-# every fetch, so anything committed directly on git.hanzo.ai is DISCARDED on the next
-# sync. Do not treat the mirror as writable, and do not reword this into a "native on
-# git.hanzo.ai" claim — that is the intended end state, not today's.
-#
-# What IS true: CI/CD runs on git.hanzo.ai — arcd executes .hanzo/workflows/ on the
-# Hanzo git-runner. Making git.hanzo.ai canonical means converting the repo
-# pull-mirror -> native and flipping the write path; an ops migration, not a config edit.
-#
-# So this nudge is a LATENCY fix, not a canonicality one: it asks Gitea to pull now
-# instead of waiting out the ~10-minute mirror interval, so arcd sees the new commit
-# sooner. Without this file the repo still mirrors — just later.
-#
-# IDEMPOTENT: mirror-sync just tells Gitea to pull HEAD, so N nudges == 1 (same latest
-# state); concurrency coalesces a burst of pushes to a single in-flight sync. FAST: no
-# checkout, one bounded curl, hard timeouts. FAIL-SOFT: a missing token or hiccup never
-# fails the push (the App webhook still mirrors). Set HANZO_GIT_TOKEN to enable the nudge.
-on:
-  push:
-    branches: [main]
-  workflow_dispatch:
-
-# Only the newest push's sync needs to run — cancel any older in-flight one (it would
-# pull a now-stale HEAD). This is what makes rapid pushes idempotent + cheap.
-concurrency:
-  group: sync-git-hanzo-ai
-  cancel-in-progress: true
-
-jobs:
-  sync:
-    # `.github/workflows` is also on Gitea's WORKFLOW_DIRS, so with Actions enabled on
-    # the mirror this file runs THERE too on every sync — where asking git.hanzo.ai to
-    # pull is circular. github.server_url is setting.AppURL on Gitea
-    # (services/actions/context.go:89), so this is the exact test for "am I upstream".
-    if: ${{ github.server_url == 'https://github.com' }}
-    runs-on: ubuntu-latest
-    timeout-minutes: 2
-    steps:
-      - name: Nudge git.hanzo.ai to pull HEAD (mirror-sync)
-        continue-on-error: true
-        env:
-          HANZO_GIT_TOKEN: ${{ secrets.HANZO_GIT_TOKEN }}
-        run: |
-          set -u
-          if [ -z "${HANZO_GIT_TOKEN:-}" ]; then
-            echo "HANZO_GIT_TOKEN not set — relying on the mirror App webhook. Skipping nudge."
-            exit 0
-          fi
-          if curl -fsS --max-time 20 --retry 2 --retry-delay 2 -X POST \
-               -H "Authorization: token ${HANZO_GIT_TOKEN}" \
-               "https://git.hanzo.ai/api/v1/repos/hanzoai/xorm/mirror-sync"; then
-            echo "git.hanzo.ai mirror-sync triggered"
-          else
-            echo "mirror-sync nudge failed (non-fatal) — the App webhook still mirrors"
-          fi