chore: improve i18n workflow to prevent stale compiled translations (#18850)

## Summary

- **Add `lingui:compile` to Dockerfile** before both the server and
frontend build stages, ensuring compiled translation catalogs are always
fresh regardless of git state
- **Add `repository-dispatch` to i18n workflows** (`i18n-push.yaml` and
`i18n-pull.yaml`) to trigger reactive automerge in `twenty-infra` when
the i18n PR is ready, replacing the 15-minute polling approach

## Context

Users sometimes see "Uncompiled message detected" errors because
releases can be cut from `main` before the i18n PR (with freshly
compiled translation catalogs) has been merged. This creates a race
condition between new translatable strings landing on `main` and their
compiled catalogs being available.

These changes fix this in two ways:
1. **Safety net in builds**: Every Docker build now compiles
translations before building, so even if compiled catalogs in git are
stale, the build artifact is always correct
2. **Faster i18n PR merges**: Instead of a 15-minute cron polling for
i18n PRs, the workflows now notify `twenty-infra` immediately when
translations are ready, reducing merge latency from ~15 minutes to ~1
minute

Companion PR in twenty-infra: twentyhq/twenty-infra
(feat/i18n-reactive-automerge)

## Test plan

- [ ] Verify `TWENTY_INFRA_TOKEN` secret is available to i18n workflows
- [ ] Docker build still succeeds with the added `lingui:compile` steps
- [ ] i18n-push triggers automerge in twenty-infra after pushing changes
- [ ] i18n-pull triggers automerge in twenty-infra after pulling
translations


Made with [Cursor](https://cursor.com)

.github/workflows/docs-i18n-pull.yaml

@@ -150,3 +150,11 @@ jobs:
           fi
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Trigger i18n automerge
+        if: github.event_name != 'pull_request' && steps.check_changes.outputs.changes_detected == 'true'
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          token: ${{ secrets.TWENTY_INFRA_TOKEN }}
+          repository: twentyhq/twenty-infra
+          event-type: i18n-pr-ready

.github/workflows/i18n-pull.yaml

@@ -138,3 +138,11 @@ jobs:
           fi
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Trigger i18n automerge
+        if: steps.compile_translations.outputs.changes_detected == 'true'
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          token: ${{ secrets.TWENTY_INFRA_TOKEN }}
+          repository: twentyhq/twenty-infra
+          event-type: i18n-pr-ready

.github/workflows/i18n-push.yaml

@@ -102,3 +102,11 @@ jobs:
           fi
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Trigger i18n automerge
+        if: steps.check_extract_changes.outputs.changes_detected == 'true' || steps.check_compile_changes.outputs.changes_detected == 'true'
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          token: ${{ secrets.TWENTY_INFRA_TOKEN }}
+          repository: twentyhq/twenty-infra
+          event-type: i18n-pr-ready