chore(sdk): bump SDK version to 1.5.3 after 1.5.2 release

[github-actions]

Automated post-release bump. Moves the VERSION file from 1.5.2 to 1.5.3 so trunk @next builds stay ahead of @latest.

[claude]

Claude finished @fmontes's task in 1m 15s —— View job

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Review

One thing to flag, otherwise clean.

⚠️ Diff vs main is 1.5.1 → 1.5.3, not 1.5.2 → 1.5.3 as the PR body claims.

• origin/main:core-web/libs/sdk/VERSION is currently 1.5.1 — main was never bumped to 1.5.2.
• The VERSION file was actually first introduced into main by an unrelated commit (c0162279 — fix(categories): default CategoryForm.active to true on omitted JSON), where it landed at 1.5.1. That's a pre-existing oddity, not caused by this PR, but it explains the gap.
• End state on main (1.5.3) is still correct for keeping @next ahead of @latest (1.5.2), so this is more of a "git history will look weird / PR description is misleading" issue than a functional problem. Worth a sentence in the description so future spelunkers don't trip on it.

Other observations (non-blocking, not introduced by this PR):

• The eight core-web/libs/sdk/*/package.json files have stale, divergent "version" values (1.1.1, 1.2.0, 1.2.5, 1.2.6, 0.0.1-beta.2, etc.) — none match VERSION. Assuming the release pipeline rewrites these at publish time from VERSION; if it doesn't, the published packages won't be 1.5.3. Worth confirming once before merging the post-release bot's output again.
• Trailing newline preserved, single-line change, no other surprises.

If VERSION is intended to be the only source of truth, ✅. If the package.json values are also read anywhere, that's a real problem and predates this PR.
• Branch: sdk/post-release-1.5.2