chore: migrate prettier hook and add setup-uv cache-suffix

Two pre-commit/CI hygiene changes:

- Migrate the prettier hook from pre-commit/mirrors-prettier@v4.0.0-alpha.8
  (deprecated, archived, pinned to a years-old alpha) to
  rbubley/mirrors-prettier@v3.8.3, the maintained successor that tracks
  stable prettier 3.x. Renovate's pre-commit manager can now track
  updates again. No content changes: prettier 3.8.3 produces identical
  output to 4.0.0-alpha.8 for this repo's YAML/JSON/Markdown files.
- Add distinct cache-suffix values to setup-uv in tests.yaml (tests)
  and pre-commit.yaml (pre-commit). Both jobs previously computed the
  same cache key on parallel runs, so one always lost the save race
  with "Failed to save: Unable to reserve cache with key" warnings.
  Distinct keys eliminate the warning at the cost of ~2x cache storage.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: bakerkj

.github/workflows/pre-commit.yaml

@@ -14,6 +14,7 @@ jobs:
         with:
           python-version: "3.14"
           enable-cache: true
+          cache-suffix: pre-commit
       - uses: actions/cache@v5.0.5
         with:
           path: ~/.cache/pre-commit

.github/workflows/tests.yaml

@@ -14,5 +14,6 @@ jobs:
         with:
           python-version: "3.14"
           enable-cache: true
+          cache-suffix: tests
       - run: uv sync --group test
       - run: uv run python -m pytest tests/ -v

.pre-commit-config.yaml

@@ -36,8 +36,8 @@ repos:
       - id: codespell
         args: ["--ignore-words-list", "hass,renderD,renderd"]
 
-  - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v4.0.0-alpha.8
+  - repo: https://github.com/rbubley/mirrors-prettier
+    rev: v3.8.3
     hooks:
       - id: prettier
         types_or: [yaml, json, markdown]