fix(release): publish generated tag in same workflow

[drewstone]

What changed

• Connects prepare-release to publish in the same Publish workflow run.
• The publish job now runs when either:
  • the workflow was triggered by a v* tag, or
  • prepare-release succeeded on a main/manual release run.
• For main/manual runs, the publish job checks out the generated tag from prepare-release.outputs.version.
• Updates README wording so it does not imply a second tag-triggered workflow is required.

Why

PR #7 correctly created v0.8.1, but GitHub did not start a second workflow from the workflow-created tag, so npm stayed at 0.8.0. This fix publishes the generated tag inside the same run.

Current release state

• Git tag v0.8.1 exists.
• npm does not have @tangle-network/traces@0.8.1.
• main package version is 0.8.1; npm latest is 0.8.0.
• After this merges, the next patch release will be 0.8.2 and should publish in the same workflow run.

Verification

• actionlint .github/workflows/publish.yml .github/workflows/ci.yml
• pnpm typecheck
• pnpm test (70/70 tests)
• pnpm build
• git diff --check
• Version math smoke: local 0.8.1, npm 0.8.0, next patch 0.8.2