ci(release): remove empty ${{ }} expression from bash comment

[mateeullahmalik]

Problem

Every workflow run of Build and Release Workflow on master since #307 landed (commit ea1a9c4) has been dying at dispatch with the workflow startup-failure fingerprint documented in that same PR — status: completed, conclusion: failure, jobs: [], run_started_at == updated_at (sub-second), workflow name reported as the raw file path rather than the name: field.

Verified on:

• Run 28756586178 — push on master @ ea1a9c4
• Run 28756630521 — push on master @ ea1a9c4
• Tag push of v2.6.0-testnet (retagged onto ea1a9c4 today) never scheduled its release job either — same root cause.

Root cause

The comment PR #307 added inside the Get tag information step's run: block contains the literal string:

# Prior implementation inlined the message via ${…{ }} interpolation,

(showing here with a ZWSP to avoid re-triggering the bug in the PR body.)

GitHub Actions validates every ${{ … }} expression in the workflow file at dispatch time — including expressions inside bash comments in run: block scalars. It does not know or care that bash would treat the line as a comment; the GHA templating engine parses the whole YAML file first. An empty ${{ }} expression is a syntactic error, so the workflow is rejected before any job is scheduled.

This is the same class of trap as #303 → #307, just at the comment layer rather than the bash-execution layer.

Fix

Rephrase the comment to describe the prior pattern in English instead of embedding the literal ${{ … }} syntax. No functional change to any step logic.

-          # Prior implementation inlined the message via \${{ }} interpolation,
-          # which let commit-body tokens (e.g. \"deadcode\") execute as bash
-          # and killed v2.6.0-testnet with exit 127. See PR history.
+          # Prior implementation inlined the message via GitHub Actions
+          # expression interpolation, which let commit-body tokens (e.g.
+          # \"deadcode\") execute as bash and killed v2.6.0-testnet with
+          # exit 127. See PR history (#303 / #307).

Verification

Pre-merge on the branch commit 1a36fc8:

• Run 28756743275 — Build and Release Workflow (correct name:, not the raw file path), `build` job dispatched (`in_progress`), `release` job `skipped` because branch push doesn't match `refs/tags/v*`. Startup-failure fingerprint is gone.

Next step (not part of this PR)

Once merged, retag `v2.6.0-testnet` onto post-merge master. The workflow's `Check if release already exists` step will hit the pre-existing draft release object and take the idempotent "Upload assets to existing release (preserve manual notes)" path, finally attaching the tarball + binary that the fleet's sn-manager needs.

Risk / rollback

Comment-only diff. Rollback = revert. No behavioural surface.