chore: prepare repository for archiving (#497)

* chore: prepare repository for archiving

Bring `main` in line with the archive plan so the repo goes quiet before
it is marked read-only on GitHub.

- Sync the README with the one shipped in the 0.19.0.post1 final release,
  so the GitHub landing page and the PyPI page tell the same story.
- Remove dependabot.yml. Daily github-actions updates with a one-day
  cooldown produced roughly twenty of the commits since v0.19.0 and would
  keep opening PRs against a repo nobody is maintaining.
- Remove the nightly cron from tests.yml, along with the now-unreachable
  "Nightly - run unit tests with Haystack main branch" step and the
  `event_name == 'schedule'` arm of the AWS auth condition.
- Remove project.yml, which added new issues to a triage board.

Archiving disables Actions anyway, but doing this first means no failing
nightly runs or stray dependabot PRs in the window before that happens.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

* chore: remove the Docusaurus API reference sync workflow

`docusaurus_sync.yml` regenerates the API reference and opens a PR into
deepset-ai/haystack writing `docs-website/reference/experiments-api/**`.
In that repo, `auto_approve_api_ref_sync.yml` auto-approves and squash-
merges any HaystackBot `sync-docusaurus-api-reference` PR touching those
paths, so the sync lands without human review.

Its tag trigger is spent — 0.19.0.post1 was the final release, and that
tag was cut from a branch where this workflow was already deleted, so no
sync PR fired. What remains is the `workflow_dispatch` trigger, and the
workflow's own warning now applies permanently: this repository has
evolved significantly since the last release (Agent, HITL, breakpoints and
mem0 were all deleted from `main` without being released). A manual run
would generate a reduced API reference and auto-merge it into Haystack,
recreating the very directory deepset-ai/haystack#12177 removes.

Removing it is the only way to close that path, since a workflow with
`workflow_dispatch` stays runnable by anyone with write access for as long
as Actions are enabled.

Keeping `pypi_release.yml`: it has no manual trigger, fires only on a
`v*` tag, and documents how the final release was produced.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: julian-risch

.github/dependabot.yml

@@ -5,10 +5,6 @@ on:
   # Activate this workflow manually
   workflow_dispatch:
 
-  # Run tests nightly against Haystack's main branch
-  schedule:
-    - cron: "0 0 * * *"
-
   push:
     branches:
       - main
@@ -105,14 +101,6 @@ jobs:
         with:
           path-to-lcov: coverage.xml
 
-      - name: Nightly - run unit tests with Haystack main branch
-        if: github.event_name == 'schedule'
-        id: nightly-haystack-main
-        run: |
-          hatch env prune
-          hatch -e test env run -- uv pip install git+https://github.com/deepset-ai/haystack.git@main
-          hatch run test:unit
-
   integration-tests:
     name: Integration / ${{ matrix.os }}
     needs: linting
@@ -140,7 +128,7 @@ jobs:
       # Do not authenticate on PRs from forks and on PRs created by dependabot
       - name: AWS authentication
         id: aws-auth
-        if: github.event_name == 'schedule' || (github.event.pull_request.head.repo.full_name == github.repository && !startsWith(github.event.pull_request.head.ref, 'dependabot/'))
+        if: github.event.pull_request.head.repo.full_name == github.repository && !startsWith(github.event.pull_request.head.ref, 'dependabot/')
         uses: aws-actions/configure-aws-credentials@e6de054238d6b7531b4efff3b6587d9aade6a06c
         with:
           aws-region: ${{ env.AWS_REGION }}