fix(cicd): use npm ci so TW v4 oxide native binary resolves on Linux

[programad]

Summary

Unblocks the v0.5.0 release pipeline. The prepare-release run for #151 failed at Run tests with:

@rocketicons/tailwind: Cannot find native binding. npm has a bug related to optional dependencies (npm/cli#4828)

Root cause

@rocketicons/tailwind's integration test loads @tailwindcss/postcss, which dynamically loads @tailwindcss/oxide, which in turn loads a per-platform native binary (@tailwindcss/oxide-linux-x64-gnu on the runner) declared as optionalDependencies.

Two factors compound:

1. actions/cache for node_modules uses restore-keys: Linux-node- — so even when the exact dependency-hash key misses, it restores an older Linux cache (from before TW v4 was added) that has no oxide-linux binary.
2. The workflow then runs npm install (not npm ci). With a partial-but-non-empty node_modules already in place, npm install does NOT detect that the Linux platform variant of an optional dep is missing — that's npm/cli#4828.

Result: tests fail at module-load with Cannot find native binding.

Fix

Replace npm install → npm ci in prepare-release.yml. npm ci:

• always wipes node_modules first (so partial restored caches don't poison the install)
• installs strictly from package-lock.json (which already records all platform variants — verified)
• correctly fetches the per-platform optional binaries for the runner OS

Verified locally with npm ci --dry-run — lockfile is in sync, no errors.

Why minimal

Only changes one line + comment. Same node_modules cache layer, same actions/cache@v4 setup, same dependency-hash key. No workflow restructuring.

Test plan

• Once merged, the develop → main PR (release: Tailwind CSS v4 + 12 months of develop (target ~v0.5.0) #151) auto-resyncs and prepare-release re-runs against develop
• All test suites pass on Linux runner (utils 22, tailwind 57, others)
• Releaser proceeds, generates release-notes.md, and uploads tag artifact