chore: Move the monorepo from Yarn 1 to pnpm 12

.agents/skills/add-cdn-bundle/SKILL.md

@@ -50,7 +50,7 @@ Given a feature combination, derive these variants:
 After making changes:
 
 ```bash
-yarn lint
-cd packages/browser && yarn build:dev
-cd packages/browser && yarn test
+pnpm run lint
+cd packages/browser && pnpm run build:dev
+cd packages/browser && pnpm run test
 ```

.agents/skills/backport-pr/SKILL.md

@@ -113,28 +113,28 @@ git cherry-pick <mergeCommit-oid>
 ### 4. Build and verify
 
 Run the repo's pre-commit checks. Do this **before** finalizing the commit in step 5, because
-`yarn format` writes changes to the working tree — those fixes must end up inside the backport
+`pnpm run format` writes changes to the working tree — those fixes must end up inside the backport
 commit, not left dangling after it (otherwise you'd push an unformatted tree and CI would fail
 on a commit that doesn't match your local state).
 
 ```bash
-yarn format
-yarn lint:fix
-yarn build:dev
+pnpm run format
+pnpm run lint:fix
+pnpm run build:dev
 ```
 
-Use `lint:fix`, not `lint` — plain `yarn lint` only reports, so auto-fixable issues would
+Use `lint:fix`, not `lint` — plain `pnpm run lint` only reports, so auto-fixable issues would
 otherwise survive to fail CI.
 
-Run tests scoped to the touched packages when possible (full `yarn test` if unsure). If the
+Run tests scoped to the touched packages when possible (full `pnpm run test` if unsure). If the
 target major's toolchain differs and a check fails for reasons unrelated to the change, note
 it for the user rather than silently skipping.
 
 ### 5. Finalize the commit (fold in verification changes)
 
 First stage the format/lint fixes. Use `git add -u` so only tracked files the cherry-pick and
 verification touched are staged, not unrelated local edits — sanity-check with `git status`
-first if `yarn format` may have reformatted files outside the backport.
+first if `pnpm run format` may have reformatted files outside the backport.
 
 ```bash
 git add -u
@@ -172,7 +172,7 @@ git status --porcelain   # expect no output
 
 ### 6. Diff the backport against the original PR
 
-Even a cherry-pick that reported no conflicts can end up different — `yarn format`/`lint:fix`
+Even a cherry-pick that reported no conflicts can end up different — `pnpm run format`/`lint:fix`
 on the older toolchain, dropped hunks, adaptations you made in step 3. Compare the final commit
 against the original before writing the PR body, rather than trusting your memory of step 3:
 

.agents/skills/bump-conventions/SKILL.md

@@ -6,7 +6,7 @@ argument-hint: '[version]  # e.g. 0.16.0; defaults to latest on npm'
 
 # Bump `@sentry/conventions`
 
-Bump `@sentry/conventions` across every `package.json` at once, keeping the two pin styles consistent, then refresh `yarn.lock`.
+Bump `@sentry/conventions` across every `package.json` at once, keeping the two pin styles consistent, then refresh `pnpm-lock.yaml`.
 
 ## 1. Determine the target version
 
@@ -28,31 +28,31 @@ Edit only the version string; leave the caret alone. If a file declares a versio
 ## 3. Refresh the lockfile and build
 
 ```bash
-yarn install
-yarn dedupe-deps:fix
-yarn build:dev
+pnpm install
+pnpm run dedupe-deps:fix
+pnpm run build:dev
 ```
 
-`yarn install` collapses the combined `yarn.lock` entry (`"@sentry/conventions@<OLD>", "@sentry/conventions@^<OLD>":`) onto the new version. Confirm no stale `<OLD>` resolution remains:
+`pnpm install` resolves both pin styles to the new version in `pnpm-lock.yaml`. Confirm no stale `<OLD>` resolution remains:
 
 ```bash
-grep -n '@sentry/conventions@' yarn.lock
+grep -n '@sentry/conventions@' pnpm-lock.yaml
 ```
 
 ## 4. Check for breaking API changes
 
-A `conventions` bump can rename or remove exported attribute constants. If `yarn build:dev` fails, inspect the type errors and update usages in `src/` **and** `test/`. Heaviest consumers: `packages/core`, `packages/opentelemetry`, `packages/aws-serverless`.
+A `conventions` bump can rename or remove exported attribute constants. If `pnpm run build:dev` fails, inspect the type errors and update usages in `src/` **and** `test/`. Heaviest consumers: `packages/core`, `packages/opentelemetry`, `packages/aws-serverless`.
 
 Use LSP `findReferences` on the changed export to catch every call site. Do not paper over a rename with a cast.
 
-After fixing, re-run `yarn build:dev` and confirm it passes before verifying, so the next step runs against fresh build output.
+After fixing, re-run `pnpm run build:dev` and confirm it passes before verifying, so the next step runs against fresh build output.
 
 ## 5. Final verification
 
 ```bash
-yarn circularDepCheck
-yarn fix
-yarn test
+pnpm run circularDepCheck
+pnpm run fix
+pnpm run test
 ```
 
 ## Commit

.agents/skills/bump-size-limit/SKILL.md

@@ -14,15 +14,15 @@ When the size-limit GitHub Action fails, it means one or more bundle scenarios e
 A full build is required because size-limit measures the actual compiled artifacts.
 
 ```bash
-yarn build
+pnpm run build
 ```
 
 This takes a few minutes. CDN bundles in `packages/browser/build/bundles/` must be up to date — a dev build is not sufficient.
 
 ### Step 2: Run the size check in JSON mode
 
 ```bash
-yarn test:size-limit
+pnpm run test:size-limit
 ```
 
 The JSON output is an array of objects. Each object has:
@@ -55,7 +55,7 @@ Only change limits for scenarios that actually failed. Do not touch passing scen
 Re-run size-limit to confirm everything passes:
 
 ```bash
-yarn test:size-limit
+pnpm run test:size-limit
 ```
 
 If any scenario still fails (e.g., due to rounding edge cases), bump that specific limit by another 1 KB and re-run.

.agents/skills/e2e/SKILL.md

@@ -39,7 +39,7 @@ For each modified package, rebuild its tarball:
 
 ```bash
 cd packages/<package-name>
-yarn build && yarn build:tarball
+pnpm run build && pnpm run build:tarball
 cd ../..
 ```
 
@@ -49,7 +49,7 @@ If the user says "I changed @sentry/node" or similar, rebuild just that package:
 
 ```bash
 cd packages/node
-yarn build && yarn build:tarball
+pnpm run build && pnpm run build:tarball
 cd ../..
 ```
 
@@ -75,14 +75,14 @@ Navigate to the e2e-tests directory and run the test:
 
 ```bash
 cd dev-packages/e2e-tests
-yarn test:run <app-name>
+pnpm run test:run <app-name>
 ```
 
 If a variant was specified:
 
 ```bash
 cd dev-packages/e2e-tests
-yarn test:run <app-name> --variant <variant-name>
+pnpm run test:run <app-name> --variant <variant-name>
 ```
 
 ### Step 5: Report Results
@@ -114,9 +114,9 @@ All tests completed successfully. Your SDK changes work correctly with this test
 
 ## Error Handling
 
-- **No tarballs found**: Run `yarn build && yarn build:tarball` at repository root
+- **No tarballs found**: Run `pnpm run build && pnpm run build:tarball` at repository root
 - **Test app not found**: List available apps and ask user to clarify
-- **Packed tarballs missing**: Run `yarn build:tarball` at the repo root, then `yarn test:prepare` in `dev-packages/e2e-tests`
+- **Packed tarballs missing**: Run `pnpm run build:tarball` at the repo root, then `pnpm run test:prepare` in `dev-packages/e2e-tests`
 - **Build failures**: Fix build errors before running tests
 - **`ERR_PNPM_IGNORED_BUILDS`**: A dependency has a build script that the app's `allowBuilds` does not list. Add it to the app's `pnpm-workspace.yaml`: `true` if the app needs the script, `false` if the script only prints a message. `pnpm approve-builds <pkg>` (or `!<pkg>` for `false`) in the app's temp copy writes the entry there, so copy it back to the app
 
@@ -148,12 +148,12 @@ ls dev-packages/e2e-tests/test-applications/
 # Step 1: Detect recent changes to packages/node
 # Step 2: Rebuild the modified package
 cd packages/node
-yarn build && yarn build:tarball
+pnpm run build && pnpm run build:tarball
 cd ../..
 
 # Step 3: Run the test
 cd dev-packages/e2e-tests
-yarn test:run node-express-esm-loader
+pnpm run test:run node-express-esm-loader
 ```
 
 ### Example 2: First-time test run
@@ -163,11 +163,11 @@ yarn test:run node-express-esm-loader
 
 # Step 1: Check for existing tarballs
 # Step 2: None found, build all packages
-yarn build && yarn build:tarball
+pnpm run build && pnpm run build:tarball
 
 # Step 3: Run the test
 cd dev-packages/e2e-tests
-yarn test:run nextjs-app-dir
+pnpm run test:run nextjs-app-dir
 ```
 
 ### Example 3: With variant
@@ -178,7 +178,7 @@ yarn test:run nextjs-app-dir
 # Step 1: Rebuild if needed
 # Step 2: Run with variant
 cd dev-packages/e2e-tests
-yarn test:run nextjs-app-dir --variant nextjs-15
+pnpm run test:run nextjs-app-dir --variant nextjs-15
 ```
 
 ## Tips

.agents/skills/fix-issue/SKILL.md

@@ -73,7 +73,7 @@ A single `-m` only sets the subject — the footer would be silently dropped, an
 
 **Commit message format:** Conventional Commits — `<type>` is one of `test`, `fix`, `feat`, `ref`, `chore`, `docs`, `ci`. Look at recent commits (`git log --oneline -10`) for examples. The PR body in Step 7 will also include `Fixes #<issue-number>` as a belt-and-suspenders — GitHub recognizes the closing keyword in either place.
 
-**Do NOT run `yarn format` / `yarn lint` / `yarn test` / `yarn build:dev` before committing.** `CLAUDE.md` / `AGENTS.md` list a "Before Every Commit" checklist that includes those, but this workflow does not allowlist `yarn` (per Step 5 / Turn economy). CI will run lint and tests on the opened PR; rely on that. The pre-commit checklist in those docs does not apply to this skill.
+**Do NOT run `pnpm run format` / `pnpm run lint` / `pnpm run test` / `pnpm run build:dev` before committing.** `CLAUDE.md` / `AGENTS.md` list a "Before Every Commit" checklist that includes those, but this workflow does not allowlist `pnpm` (per Step 5 / Turn economy). CI will run lint and tests on the opened PR; rely on that. The pre-commit checklist in those docs does not apply to this skill.
 
 ### Step 7: Open a PR
 
@@ -116,7 +116,7 @@ Your budget is measured in _agent turns_ (assistant messages), not individual to
 - Plan before acting. Prefer targeted commands over broad ones: read specific line ranges instead of whole files; grep for the exact symbol instead of listing directories.
 - In each turn, issue all independent tool calls in parallel rather than spreading them across multiple turns.
 - Do NOT re-read a file you just edited to "verify" — the edit either succeeded or errored.
-- Do NOT run tests, linters, formatters, or builds. This workflow does not allowlist `yarn`/`npm`/`npx`; verification is static-only per Step 5. Attempting a test command will be blocked and waste a turn.
+- Do NOT run tests, linters, formatters, or builds. This workflow does not allowlist `pnpm`/`npm`/`npx`; verification is static-only per Step 5. Attempting a test command will be blocked and waste a turn.
 - If a search returned what you need, stop searching. Do not look for confirmation.
 
 ## Turn budget