Release 9.3.0: water and caffeine import, honest Effort, and an Oura resting-HR fix

[ryanbr]

Release notes for 9.3.0, covering everything merged since v9.2.1 (43 PRs), plus the in-app What's New entry and the version bumps.

What's here

• docs/releases/v9.3.0.md — the release notes, with the whatsnew front-matter the generator reads. Title translations are supplied for all five locales, so the generator has no English fallback to warn about.
• AppChangelog.kt / AppChangelog.swift + six strings.xml — generated by Tools/appchangelog-gen.py, not hand-written, so both platforms carry byte-identical items and Android gets a localised title rather than a raw literal.
• CHANGELOG.md — a 9.3.0 section in the existing house format.
• Versions — MARKETING_VERSION 9.2.2 → 9.3.0, versionName 9.2.2 → 9.3.0, versionCode 305 → 306.

Why the notes lead with "Scores that change"

Three merges move numbers users have already seen, and one needs an action from them. Burying that under "Fixed" would have people reading a changed Effort score as a new bug:

• Strain: weight each HR sample by its own gap, not the window's first one #963 — strain now weights each HR sample by its own gap instead of the window's first. Gappy days move in either direction.
• No effort at all on a day is hard to believe, HR always does something #983 / Workout effort score vs total not in sync #950 — a saved workout is scored against measured resting HR, not a hardcoded 60. Below 60 Effort rises, above 60 it falls.
• feat(sleep): re-tune SleepStagerV2 deep boundary on DREAMT (n=100 gold) #348 — sleep staging forbids wake → deep/REM.
• fix(import): select Oura's main sleep session for the daily rollup #375 — corrects the Oura importer, not rows already written, so it needs a re-import to take effect. Called out explicitly for that reason.

The iPhone permission prompt from #974 is also flagged, since an existing install will see a Health dialog it has never seen before and that is otherwise alarming.

Verification

• Tools/i18n_audit.py --ci origin/main — exit 0. The new title key is present in all six strings.xml with real translations, French apostrophe correctly XML-escaped.
• Tools/doc_comment_lint.py — clean.
• Kotlin: full src/main/java compile. 2517 errors vs main's 2516; the single delta is one more unresolved reference: R in AppChangelog.kt, which already has 270 of them because R isn't generated in an ad-hoc classpath. Exactly +1 for the +1 new uiString(R.string…) line, and Gradle generates the field from the strings.xml entry above.
• Swift: swiftc -parse clean on AppChangelog.swift.
• Contributors collected with Tools/release-contributors.sh v9.2.1 per CLAUDE.md, credited by @handle, third-party only.

Note, not fixed here

CHANGELOG.md has no 9.2.0 or 9.2.1 section — its newest entry before this was 9.1.0, so this commit makes the file read 9.1.0 → 9.3.0. Both versions do have docs/releases/ notes and in-app entries, so only that one file has the gap. Backfilling it is a separate change and not mixed into a release commit.