Remove disabled release-all.yml workflow

[peter-vapi]

Description

• Deletes .github/workflows/release-all.yml. Every one of its 76 lines has been a comment since 7232d96 (2025-06-20, "SDK don't just have one version, they have multiple versions"), so it has no on: and no jobs:.
• GitHub still parses it on every push to every branch and records a zero-job failure ("No event triggers defined in on"). There are 1,223 retained runs, and none ever passed.
• Nothing depends on it. No workflow references it, and the main rulesets require a PR plus one approval but no status checks.
• What it used to do already happens elsewhere. Docs publishing runs through publish-docs.yml, and SDK releases run through the per-language release-*-sdk.yml workflows, which are triggered by hand. (release-java-sdk.yml is itself dead and tracked separately in PRO-4069.)
• The only visible effect of this PR is that the red X on every push goes away.

Linear: PRO-4017
OpenCode session ID: ses_ee28ca0d0ffeKUW3O43fB8lpu0

Testing Steps

• No rendered pages or snippets change. Only a workflow file is removed, so fern docs dev output is unaffected.
• grep -rn release-all across the repo after the deletion returns nothing.
• After merge, confirm no new runs appear for "release-all" in the Actions tab.

[lightsage-app]

Lightsage docs evals

Lightsage could not queue docs evals for this PR.

Docs URL: https://vapi-preview-01a1311f-4ec3-723c-a86a-b348eec090e3.docs.buildwithfern.com
Commit: 73318b6
Reason: No custom evals are selected for GitHub PR evals. Open Lightsage > Custom Evals and enable the GitHub checkbox for at least one custom eval.

[github-actions]

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