feat(yarn): add yarn command support with smart delegation

CHANGELOG.md

@@ -68,6 +68,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Features
 
+* **yarn:** add yarn command support with smart delegation to specialized filters (60-99% reduction)
+* **yarn:** auto-detect known tools (vitest, tsc, eslint, biome, next, prettier, playwright) and delegate to existing RTK filters
+* **yarn:** add generic filter for yarn Classic v1 and Berry v2+ boilerplate stripping
+* **yarn:** add install/add/remove filter — strip progress phases, info, warnings (75% reduction)
+* **yarn:** add discover/rewrite rules for yarn commands and yarn-prefixed tool invocations
 * **ruby:** add RSpec test runner filter with JSON parsing and text fallback (60%+ reduction)
 * **ruby:** add RuboCop linter filter with JSON parsing, grouped by cop/severity (60%+ reduction)
 * **ruby:** add Minitest filter for `rake test` / `rails test` with state machine parser (85-90% reduction)

README.md

@@ -423,6 +423,7 @@ Blocked on upstream BeforeToolCallback support ([mistral-vibe#531](https://githu
 | `kubectl get/logs` | `rtk kubectl ...` |
 | `curl` | `rtk curl` |
 | `pnpm list/outdated` | `rtk pnpm ...` |
+| `yarn build/lint/install` | `rtk yarn ...` |
 
 Commands already using `rtk`, heredocs (`<<`), and unrecognized commands pass through unchanged.
 

scripts/test-all.sh

@@ -241,6 +241,17 @@ section "Npm / Npx (new)"
 assert_help    "rtk npm"                      rtk npm
 assert_help    "rtk npx"                      rtk npx
 
+# ── 8b. Yarn ──────────────────────────────────────────
+
+section "Yarn"
+
+assert_help    "rtk yarn"                     rtk yarn
+assert_help    "rtk yarn --help"              rtk yarn --help
+
+if command -v yarn >/dev/null 2>&1; then
+    assert_ok  "rtk yarn --version"           rtk yarn --version
+fi
+
 # ── 9. Pnpm ─────────────────────────────────────────
 
 section "Pnpm"
@@ -465,6 +476,7 @@ section "Global flags"
 
 assert_ok      "rtk -u ls ."                  rtk -u ls .
 assert_ok      "rtk --skip-env npm --help"    rtk --skip-env npm --help
+assert_ok      "rtk --skip-env yarn --help"   rtk --skip-env yarn --help
 
 # ── 32. CcEconomics ─────────────────────────────────
 

src/cmds/js/mod.rs

@@ -9,3 +9,4 @@ pub mod prettier_cmd;
 pub mod prisma_cmd;
 pub mod tsc_cmd;
 pub mod vitest_cmd;
+pub mod yarn_cmd;