feat(pnpm): add rtk pnpm [run] <script> with smart filter routing

[denneulin]

Summary

• Add rtk pnpm run <script> and rtk pnpm <script> shorthand with smart routing to specialized filters
• Strip pnpm boilerplate (lifecycle headers, script echo, "Done in Xs", ELIFECYCLE errors, progress bars)
• Two-tier script routing: static name matching (test, lint, typecheck, vitest, prettier, format) +
  package.json auto-detection for custom scripts (e.g., test:e2e → detects playwright test →
  PlaywrightParser)
• Promote filter_tsc_output, filter_generic_lint, extract_test_summary to pub(crate) for cross-module
  reuse

Token Savings

Script	Route	Expected Savings
pnpm [run] test (vitest)	VitestParser	90%+
pnpm [run] typecheck (tsc)	filter_tsc_output	80%+
pnpm [run] lint (eslint)	filter_generic_lint	80%+
pnpm [run] prettier --check	filter_prettier_output	70%+
pnpm [run] test:e2e (playwright)	PlaywrightParser	80%+
pnpm [run] build (unrouted)	Boilerplate strip only	30-50%

How It Works

• rtk pnpm run test → PnpmCommands::Run → run_script("test") → boilerplate strip → TestRunner filter
• rtk pnpm test → PnpmCommands::Other → is_pnpm_script("test") → run_script("test")
• rtk pnpm test:e2e → reads package.json → detects playwright test → PlaywrightParser
• rtk pnpm store prune → is_pnpm_script("store") = false → passthrough

Test plan

• 25 new unit tests (boilerplate filtering, static routing, prefix matching, prefix exclusions,
  apply_filter labels, integration, is_pnpm_script)
• 4 Clap parsing tests (basic, with args, colon script, shorthand falls to Other)
• cargo fmt --all && cargo clippy --all-targets && cargo test --all — 437 tests pass
• Manual test with real pnpm project: rtk pnpm run test, rtk pnpm test, rtk pnpm run lint