feat(mobile): add slug suffix to inbox report deep links

[Gilbert09]

Summary

Port of the desktop PR #2298 to the mobile app: when the "Discuss this report" flow builds a link back to a report, append the slugified title as a trailing path segment so shared/copied links read like posthog://inbox/<reportId>/fix-inbox--Add-foo instead of just the UUID. The slug is purely cosmetic — receivers ignore everything past the UUID.

• apps/mobile/src/lib/deep-links.ts

  • Adds slugifyTitle(title) mirroring buildInboxDeeplink's slug rules in apps/code/src/shared/deeplink.ts exactly (NFD-fold accented Latin, preserve URL-unreserved punctuation _ . ~, collapse colon-with-other-chars runs to --, single colon-only runs to -, strip leading/trailing hyphens).
  • Adds inboxReportShareUrl(reportId, title?) that produces the slug-suffixed posthog://inbox/<id>/<slug> custom-scheme URL (no slug when the title is empty / slugifies to empty).
  • Extends externalUrlToAppPath to strip a trailing slug from inbox custom-scheme and universal-link URLs so notification-tap navigation lands on the bare /inbox/<id> path. Mirrors the desktop receiver, which also ignores the slug.

• apps/mobile/src/app/inbox/[id].tsx → apps/mobile/src/app/inbox/[...id].tsx

  • Converts the route to a catch-all so expo-router resolves both /inbox/<id> and /inbox/<id>/<slug> to the same report screen (the OS-level deep-link entry doesn't go through externalUrlToAppPath, so route-level tolerance is the load-bearing fix).
  • Pulls reportId from the first catch-all segment and passes report.title into DiscussReportSheet.
  • _layout.tsx Stack.Screen registration updated to inbox/[...id].

• apps/mobile/src/features/inbox/components/DiscussReportSheet.tsx

  • Accepts optional reportTitle?: string | null and builds the link via inboxReportShareUrl(reportId, reportTitle) (replacing the bare customSchemeUrl(paths.inboxReport(reportId))).
  • Still hands the resulting URL to buildDiscussReportPrompt from @posthog/shared unchanged.

• apps/mobile/src/lib/deep-links.test.ts

  • Covers the slug rules (accented-fold, colon-run -- vs single -, URL-unreserved punctuation passthrough, punctuation-collapse, trim) mirroring apps/code/src/shared/deeplink.test.ts.
  • Covers inboxReportShareUrl (empty title, slug-empty title, colon-run convention).
  • Covers inbound path tolerance: a trailing slug segment is stripped from both posthog://inbox/<id>/<slug> and https://code.posthog.com/inbox/<id>/<slug>, including query-string preservation.

No changes to apps/code or shared-package code — buildDiscussReportPrompt from @posthog/shared is reused as-is.

Test plan

• pnpm --filter @posthog/mobile test — 156/156 passing including the new slug + inbound-path cases.
• pnpm --filter @posthog/mobile lint — clean.
• Manual: tap posthog://inbox/<id> on a device → routes to the report.
• Manual: tap posthog://inbox/<id>/some-slug on a device → routes to the same report (slug ignored).
• Manual: tap https://code.posthog.com/inbox/<id>/some-slug (universal link) → routes to the same report.
• Manual: open a report, hit "Discuss" → confirm the prompt embeds a posthog://inbox/<id>/<slug> URL with the slugified title.

[greptile-apps]

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
apps/mobile/src/lib/deep-links.test.ts:9-15
Several `it()` blocks exercise multiple independent inputs with separate `expect()` calls. The team's style guide prefers parameterised tests (`it.each`) so each input/expected pair gets its own test name and failure line when it breaks. The same pattern appears in `slugifyTitle` ("returns an empty string…" — 5 cases), `inboxReportShareUrl` ("returns just the UUID…" — 4 cases, "omits the slug…" — 2 cases), and `externalUrlToAppPath` ("ignores URLs…" — 2 cases).

```suggestion
  it.each([
    [null],
    [undefined],
    [""],
    ["   "],
    [":::"],
  ])("returns an empty string when the title is %s", (input) => {
    expect(slugifyTitle(input)).toBe("");
  });
```

_{Reviews (1): Last reviewed commit: "feat(mobile): add slug suffix to inbox r..." | Re-trigger Greptile}