chore: repo moved to gitea/agents — update self-references

Repo transferred ffaerber/agents -> gitea/agents. Point the scripts checkout (agent.yml
repository:), the standard caller (uses:), and the README at gitea/agents. The trigger gate still
keys on the maintainer 'ffaerber' (unchanged).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/agent.yml

@@ -1,6 +1,6 @@
 name: agent
 # Reusable AI-agent workflow, shared across repos. A caller repo triggers on issue_comment/issues
-# and invokes this via:  uses: ffaerber/agents/.gitea/workflows/agent.yml@main  (secrets: inherit).
+# and invokes this via:  uses: gitea/agents/.gitea/workflows/agent.yml@main  (secrets: inherit).
 # The gate + steps run in the caller's event context (github.event.* / github.repository are the caller's).
 on:
   workflow_call:
@@ -54,7 +54,7 @@ jobs:
       - name: Fetch shared agent scripts (this repo)
         uses: actions/checkout@v4
         with:
-          repository: ffaerber/agents
+          repository: gitea/agents
           ref: main
           path: .agents-workflow
           token: ${{ secrets.GITEA_TOKEN }}