[Feature] Stop CI from running on release tags to avoid duplicate builds

[mbe24]

Problem

Pushing a release tag (for example v0.4.0) currently triggers both:

1. the regular CI workflow, and
2. the release workflow.

Because the tagged commit has already run CI on main, this duplicates compute/time and adds noise in Actions history.

Design

Keep responsibilities split:

1. CI workflow handles PR and main branch validation.
2. Release workflow handles tag-based release execution.

Implement by removing tag-trigger activation from ci.yml, while keeping tag trigger in release.yml.

Scope

• Remove push.tags: ["v*"] from .github/workflows/ci.yml.
• Keep all existing CI jobs/conditions unchanged.
• Keep .github/workflows/release.yml triggers unchanged.

Boundary

• No changes to release publishing steps.
• No new workflows.
• No change to branch/PR CI quality gates.

Acceptance Criteria

• Push to main triggers CI as before.
• Push of v* tag triggers Release workflow.
• Push of v* tag no longer triggers CI workflow.
• Manual release via workflow_dispatch remains functional.

Context

This is a small workflow trigger cleanup that reduces duplicate builds while preserving current release behavior.

• GitHub Actions workflow syntax: https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions
• GitHub Actions events for push/tags: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#push