ci: ensure dependencies are always installed in workflow

Remove conditional dependency installation in linter and build jobs.
The previous condition `if: needs.setup.outputs.cache-hit != 'true'`
caused CI failures when node_modules cache was incomplete or corrupted,
leading to missing type definitions during lint and type checking.

Changes:
- Always run `pnpm install --frozen-lockfile` in linter and build jobs
- pnpm store cache ensures no redundant downloads
- More reliable CI execution with proper dependency resolution

Fixes: https://github.com/molvqingtai/WebChat/actions/runs/18172807108

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -54,7 +54,6 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-pnpm-
       - name: Install dependencies
-        if: needs.setup.outputs.cache-hit != 'true'
         run: pnpm install --frozen-lockfile
       - run: pnpm run lint
       - run: pnpm run check
@@ -80,6 +79,5 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-pnpm-
       - name: Install dependencies
-        if: needs.setup.outputs.cache-hit != 'true'
         run: pnpm install --frozen-lockfile
       - run: pnpm run build