DIVE-3578: rebrand the mobile fork as 5dive (name, icon, first-run copy)

[lodar]

lodar's verdict on the DIVE-3575 sideload: "i wanted 5dive app not buzz app - change icon and name and fix obvious missteps to make it ours." Branding pass only, no feature changes.

• app_name / APP_DISPLAY_NAME / CFBundleName / MaterialApp(title:) -> 5dive
• applicationId xyz.block.buzz.mobile -> com.fivedive.app (new install identity, installs alongside a real Buzz instead of colliding on signature). Kotlin namespace deliberately unchanged so no source moves and upstream merges stay cheap.
• Launcher/round/adaptive-foreground/splash regenerated from app/public/icon-512.png (the 5dive mark); adaptive background #1A1A1F.
• 8 user-visible strings that named OUR app now say 5dive; Buzz Desktop, buzz://, relay/protocol nouns and the persisted 'buzz' theme key left alone.
• scripts/test-mobile-worktree-overrides.sh + mobile-worktree-overrides.sh + mobile-worktree-clean.sh hard-coded the old name and package id; updated. Run locally: 33 ok / 0 failures.
• sideload-apk.yml now publishes a prerelease asset (an Actions artifact link needs a login and is dead on a phone).

APK: https://github.com/5dive-ai/buzz/releases/download/mobile-sideload-5dive-2/5dive-2.apk (anonymous 200, application/vnd.android.package-archive, 194 MB).
Verified in the shipped bytes: package com.fivedive.app, resources app_name=5dive with no bare "Buzz" left in resources.arsc, all 20 mipmap PNGs byte-identical to this tree, and kernel_blob.bin contains 'Welcome to 5dive' / 'Join this community?' with zero hits for the old strings.

Dart unit tests were updated to match the copy but NOT executed: no flutter/java/Android SDK on this host, and ci.yml only triggers on push to main/release.

[lodar]

Iteration 2 (41b87d7)

Addresses quinn's three rejects on 46d26ce.

1. Format check red → green. invite_join_sheet.dart: 'Join this community?' → 'Join this 5dive community?'. Fixes both findings at once — it moves the brand instead of dropping it (the point of the pass), and it restores the width dart format's tall style needs to keep the Text(...) split. Mobile / Format check: success on run 32117467483.

2. The tests finally ran. With Format green, the rest of the sequential Mobile job graded: Analyze: success, Test: success, Build Android debug APK: success. That closes the iteration-1 disclosed gap — the 5 updated Dart test files had never executed anywhere.

3. Welcome-screen logo (lodar's new ask). pairing_welcome_view.dart hero: TappableFlappingBee(width: 76) → FiveDiveMark(height: 72), a new widget in shared/widgets/fivedive_mark.dart rendering an alpha-mask silhouette of the 5dive "5" cut from the same app/public/icon-512.png the launcher icons came from, tinted to _onboardingInk via Image.asset(color:) (BlendMode.srcIn). Moved with it: the direct import in pairing_page.dart (would be unused_import) and pairing_page_test.dart's find.byType assertion.

TappableFlappingBee and flapping_bee.dart are kept — the painter still drives BeeRefreshIndicator on 5 screens. An unreferenced public class in lib/ raises no analyzer warning and deleting it would be a merge conflict for nothing. The tap-to-flutter easter egg does not survive on the welcome screen; that was deliberate.

Checked in the downloaded release bytes (5dive-3.apk, sha256 aee8b249…)

• assets/flutter_assets/assets/images/5dive-mark.png sha256 34455c63… — byte-identical to the source tree.
• kernel_blob.bin: 2 hits each for assets/images/5dive-mark.png, Welcome to 5dive, Join this 5dive community?, Starting 5dive, full 5dive identity; 0 for Welcome to Buzz, Join this Buzz community?, and the generic Join this community?.
• Binary manifest: com.fivedive.app ×7; the single xyz.block.buzz.mobile is the Kotlin namespace (MainActivity), deliberately unchanged.
• Release asset anon curl -sIL → 200, application/vnd.android.package-archive, 194,121,506 bytes.

Not done

• No device render. No Flutter on the agent hosts, so the mark's size (48×72 inside the 136 circle, vs the bee's 76×50) is a judgment call, not a measurement. Different visual weight — taller and narrower. lodar's eyes are the check.
• mobile/assets/images/buzz-icon.png is still registered in pubspec.yaml and ships in the APK. It is referenced by nothing in lib/ — a dead asset, but it is still a bee in our bytes.
• BeeRefreshIndicator is still a bee on 5 screens (forum, activity ×2, pulse, channels). Deeper than a branding pass.
• Carried from iteration 1 and unchanged: iOS AppIcon asset set not replaced; theme picker still lists a theme labelled "Buzz".

Wiki updated: community/wiki/rebranding-the-buzz-mobile-fork-what-is-cheap-and-what-fights-back.md §9 (a logo on the welcome screen is a widget swap, not an asset swap), plus the index.md line.

Pairing QR is not on this row — filed as DIVE-3581 (live desktop session + an identity decision that is lodar's).