chore(release): bump to 0.70.0 (versionCode 75) for wave animation

Ship the harmonic wave rework (a8d8067). Bump versionCode 74→75 and
versionName 0.69.0→0.70.0 in build.gradle and version.ts (kept in sync),
build the debug APK, and publish it plus version.json to the dl server.
Devices on 0.69.0 now see the update banner; nothing changed in the
auto-update mechanism — it simply had no newer build to offer until now.

Constraint: APP_VERSION_CODE in version.ts must equal build.gradle
versionCode, else the update modal mis-fires.
Confidence: high
Scope-risk: system
Reversibility: moderate
Directive: future releases follow proxy/DEPLOY.md "앱 릴리스" steps.
Tested: aapt confirms APK versionCode=75/0.70.0; server /dl/version.json
returns 75 and /dl/seacatch.apk returns HTTP 200 (28.5MB) via Caddy.
Not-tested: on-device banner→download→install round trip.
Related: a8d8067, proxy/DEPLOY.md

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