release: prepare 0.5.0

[sjungwon03]

Version, build numbers, and the store copy. No promotion — merging dev into
main is what releases.

	before	after
package.json version	0.4.1	0.5.0
expo.version	0.4.1	0.5.0
iOS build number	5	6
Android version code	4	5

Both stores refuse an upload whose build number is not higher than the last one
they saw, even for a rejected submission — so these move on every upload, not
every release.

What ships

Eighteen commits since v0.4.1: a timeline shaped for a phone, clip thumbnails,
titles, speed, transitions that render rather than only preview, colour, rotation
and position in the frame, audio waveforms, the AI reaching edits it previously
could not, and ads mediated by Unity LevelPlay rather than AdMob.

The four store note files are rewritten for that. The Play English copy had to be
cut: Play allows 500 characters and the full list ran to 574 — caught by the test
rather than by the console, which is the point of keeping this copy in the
repository.

Before promoting

• The store privacy answers need updating. Five ad SDKs ship now where one
  did: Data Safety and App Privacy must declare device or other identifiers,
  collected by a third party, for advertising. Reviewers check that against the
  SDKs in the binary rather than against the form. mobile/RELEASING.md has the
  detail.
• AppLovin is not bidding. Its adapter is in the binary, but the network has
  no instance configured for this app in the LevelPlay dashboard — as it stands
  the release ships an SDK that is declared and never asked to bid.
• AdBanner has not been seen to render. Both placements serve through
  LevelPlay's Test Suite, which uses its own views; the app's own banner mounts a
  legacy view manager under the New Architecture, where the failure mode is a
  banner that never appears.

Closes #270

🤖 Generated with Claude Code

[sjungwon03-ai]

Approved. Version and mobile build numbers are consistent and advanced from v0.4.1; store notes are within their platform limits. Exact-head CI passed, including iOS and Android native builds.