refactor: remove shared/common.sh and 27 subprocess-heavy test files (#1728)

shared/common.sh (3852 lines) was dead code — the entire architecture
was rewritten to TypeScript in cli/src/. No agent scripts source it
anymore. The only consumer was github-auth.sh which just needed 4
log functions (now inlined).

Remove 27 test files that spawned ~800+ real bash/bun subprocesses per
run (the root cause of slow bun test). Every shared-common-*.test.ts
file forked a real bash shell per test case to source shared/common.sh.
CLI subprocess tests spawned `bun run index.ts` per assertion. These
were integration tests, not unit tests.

Also removes:
- mock-tests CI job from test.yml (ran test/mock.sh which opens browser)
- Stale plan files referencing deleted infrastructure
- All CLAUDE.md/README.md references to the old lib/common.sh pattern

Co-authored-by: lab <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/test.yml

@@ -30,52 +30,3 @@ jobs:
       - name: Verify cloud bundles build
         run: bun run cli/build-clouds.ts
 
-  mock-tests:
-    name: Mock Tests
-    runs-on: ubuntu-latest
-    timeout-minutes: 10
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Setup Bun
-        uses: oven-sh/setup-bun@v2
-
-      - name: Install dependencies
-        working-directory: cli
-        run: bun install
-
-      - name: Run mock tests
-        id: tests
-        env:
-          NO_COLOR: 1
-        run: |
-          set +e
-          bash test/mock.sh 2>&1 | tee /tmp/mock-output.log
-          echo "exit_code=${PIPESTATUS[0]}" >> "$GITHUB_OUTPUT"
-
-      - name: Post summary
-        if: always()
-        run: |
-          echo '## Mock Test Results' >> "$GITHUB_STEP_SUMMARY"
-          echo '```' >> "$GITHUB_STEP_SUMMARY"
-          grep -E 'Results:' /tmp/mock-output.log >> "$GITHUB_STEP_SUMMARY" || true
-          echo '```' >> "$GITHUB_STEP_SUMMARY"
-          FAILURES=$(grep '✗' /tmp/mock-output.log | head -50)
-          if [[ -n "$FAILURES" ]]; then
-            echo '' >> "$GITHUB_STEP_SUMMARY"
-            echo '<details><summary>Failures (first 50)</summary>' >> "$GITHUB_STEP_SUMMARY"
-            echo '' >> "$GITHUB_STEP_SUMMARY"
-            echo '```' >> "$GITHUB_STEP_SUMMARY"
-            printf '%s\n' "$FAILURES" >> "$GITHUB_STEP_SUMMARY"
-            echo '```' >> "$GITHUB_STEP_SUMMARY"
-            echo '</details>' >> "$GITHUB_STEP_SUMMARY"
-          fi
-
-      - name: Check results
-        if: always()
-        run: |
-          if [[ "${{ steps.tests.outputs.exit_code }}" != "0" ]]; then
-            echo "Mock tests failed (exit code ${{ steps.tests.outputs.exit_code }})"
-            exit 1
-          fi