Use push-triggered deploy for GitHub Pages and remove manual dispatch

[Evenss]

Motivation

• Simplify CI by removing the manual workflow_dispatch deploy flow and make Pages deployment run automatically on push to main.

Description

• Remove the workflow_dispatch inputs block from .github/workflows/pages.yml.
• Replace conditional checks that used github.event_name == 'workflow_dispatch' && inputs.deploy with checks against github.event_name == 'push' for setup and artifact upload steps.
• Update the deploy job to run when github.event_name == 'push' instead of relying on manual input.

Testing

• No automated tests were run as part of this PR; the updated workflow will run on the next push to main and can be validated by the resulting GitHub Actions run.

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Codex Task