chore(CI): fix workflow triggers and regenerate OpenAPI specs on stable35

[oleksandr-nc]

Every PR targeting stable35 is currently unmergeable, and the openapi check is red on all of them. Neither has anything to do with the PRs' own contents.

1. Tests-OK / Tests-Deploy-OK / TestsSpecial-OK never report

All tests*.yml workflows were carried over from main when the branch was cut and still say:

on:
  pull_request:
    branches: [main]
  push:
    branches: [main]

A PR based on stable35 never matches, so the workflows never start and their summary jobs never post a status. Since all three are required status checks on stable35, branch protection leaves every PR at mergeable_state: blocked indefinitely. The server checkouts inside them are also still ref: master, so even when run they would have tested against server master.

#989 adjusted lint.yml and phpunit.yml but skipped this pass. This change mirrors what #873 did for stable34:

• branches: [main] → branches: [stable35]
• ref: master → ref: stable35 (nextcloud/server and nextcloud/notifications; nextcloud/notes stays on main, as on stable34)
• -e SERVER_BRANCH=stable35 on the six docker run invocations that launch the prebuilt nextcloud-dev-php83 image (the nginx and ExApp containers are untouched)
• phpunit.yml push trigger → stable35 (its matrix was already correct)

2. openapi fails on every stable35 PR

#989 changed appinfo/info.xml from <licence>agpl</licence> to <licence>AGPL-3.0-or-later</licence> without re-running composer run openapi, so the committed specs are stale:

     "license": {
-        "name": "agpl"
+        "name": "AGPL-3.0-or-later"
     }

Regenerated with composer run openapi (nextcloud/openapi-extractor ^1.8.7); the licence name is the only difference.

Not addressed here

Block merges during freezes fails because nextcloud/server stable35/version.php is at 35.0.0 RC4. That is the workflow working as intended and will clear once 35.0.0 is released.

Note

This will be the first time the deploy/integration suites actually run against server stable35, so genuine failures may surface. Draft until they are green.