fix(init): preserve scope/path separators in project slugs

[MathurAditya724]

Summary

sentry init produces unreadable project slugs for monorepo / npm-scoped
package names. Reported case: `package.json` with `"name": "@t3tools/web"`
created a Sentry project with slug `t3toolsweb` instead of `t3tools-web`.

Root cause

`slugify()` in `src/lib/utils.ts` mirrors Sentry's frontend canonical
implementation
(`static/app/utils/slugify.tsx`),
which strips invalid characters (including `@` and `/`) in a single pass.
For npm scopes and monorepo path segments this destroys structural
information — `/` should be preserved as a hyphen, not silently dropped.

Fix

Normalize `/` and `\` to a space before the invalid-character strip
step. The existing `[-\s]+` collapse rule then folds them into hyphens.

```ts
return name
.normalize("NFKD")
.toLowerCase()
.replace(/[\\/]+/g, " ") // ← new
.replace(/[^a-z0-9_\\s-]/g, "")
.replace(/[-\s]+/g, "-")
.replace(/^-|-$/g, "");
```

Behavior change

Input	Before	After
`@t3tools/web`	`t3toolsweb`	`t3tools-web`
`@scope/pkg`	`scopepkg`	`scope-pkg`
`packages/api`	`packagesapi`	`packages-api`
`apps\\api`	`appsapi`	`apps-api`
`@scope/My App`	`scopemy-app`	`scope-my-app`

All other inputs unchanged:

• `My Cool App` → `my-cool-app`
• `Café Project` → `cafe-project`
• `my_app` → `my_app`
• `---foo---` → `foo`

Tests

• `test/lib/utils.test.ts` (new) — unit cases for JSDoc examples, npm
  scopes, monorepo paths, edge cases (empty, all-invalid input,
  leading/trailing separators).
• `test/lib/utils.property.test.ts` (new) — invariants for any input:
  • Output always matches `/^[a-z0-9_-]*$/`
  • Output never starts/ends with `-`, never contains `--`
  • `slugify(slugify(x)) === slugify(x)` (idempotent)
  • For any `a/b` with both segments alphanumeric, output is exactly `a-b`

26 new tests pass; full suite (6,343 tests) passes; lint clean; typecheck clean.

Note for affected users

Anyone who previously ran `sentry init` against a scoped-package project
got a Sentry project with the broken slug (e.g. `t3toolsweb`). After this
fix lands, a re-run of `sentry init` will:

1. Compute the new (correct) slug, e.g. `t3tools-web`
2. Find no existing project with that slug
3. Create a new project named `@t3tools/web` with slug `t3tools-web`
4. Leave the old `t3toolsweb` project orphaned

The old project can be deleted via the Sentry UI or
`sentry project delete /t3toolsweb`. We're not adding a fallback
lookup ("if new slug not found, try old slug") because it adds
significant complexity for a small affected user base, and the orphaned
project is easy to clean up manually.

Out of scope

• Not normalizing other characters (`:`, `.`, `+`) — only `/` and `\`
  are unambiguous structural separators. Targeting just the reported bug.
• Not changing the function signature — the one-line behavior tweak is
  safer than expanding the API.
• Not changing the upstream Sentry frontend `slugify` — this is a CLI
  improvement specifically for input shapes (npm scopes, monorepo paths)
  the CLI receives that the web UI typically doesn't.

[github-actions]

PR Preview Action v1.8.1
🚀 View preview at https://cli.sentry.dev/_preview/pr-886/
Built to branch gh-pages at 2026-04-29 19:03 UTC. Preview will be ready when the GitHub Pages deployment is complete.

[github-actions]

Codecov Results 📊

✅ 6343 passed | Total: 6343 | Pass Rate: 100% | Execution Time: 0ms

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +26
Passed Tests	📈 +26
Failed Tests	—
Skipped Tests	—

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 13883 uncovered lines.
❌ Project coverage is 74.87%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
- Coverage    75.97%    74.87%     -1.1%
==========================================
  Files          294       294         —
  Lines        54449     55248      +799
  Branches         0         0         —
==========================================
+ Hits         41365     41365         —
- Misses       13084     13883      +799
- Partials         0         0         —

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