fix(core): harden fetchImage data URLs + base64 padding test coverage

[ignaciosantise]

Addresses the two findings from the Claude review on #575.

Issue 1 — base64 padding untested (MEDIUM, test_coverage)

Every existing fetchImage test used a byte length divisible by 3 (6 and 3 bytes), so the = / == padding branches in _arrayBufferToBase64 were never executed — despite nearly all real images having byte counts not divisible by 3. Added two cases:

• [0x66] ("f") → Zg==
• [0x66, 0x6f] ("fo") → Zm8=

Issue 2 — content-type params leaked into data URL (LOW, correctness)

fetchImage embedded the raw content-type header, so image/svg+xml; charset=utf-8 produced a malformed data:image/svg+xml; charset=utf-8;base64,... that strict parsers may reject. Now strips at the first ; before building the data URL, with a regression test.

Testing

• FetchUtil.test.ts: 21 passing (3 new)
• eslint clean on changed files
• changeset added (patch, all 9 published packages)

🤖 Generated with Claude Code

[changeset-bot]

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Latest commit: e0f6380

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[claude]

Claude finished @ignaciosantise's task in 2m 23s —— View job

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Code Review

• Gather context
• Read changed files
• Review code
• Post findings

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🔄 Incremental Review: First review of this PR.

Found 2 issue(s)

Issue 1: Misleading test description for double-char (==) padding case

ID: fetchutil-test-desc-padding-a3c1
File: packages/core/src/tests/utils/FetchUtil.test.ts:145
Severity: LOW
Category: code_quality

Context:

• Pattern: Test name says "should produce correct single-char padding (==) for a one-byte remainder" but == is two characters (double padding), not single.
• Risk: Future readers mapping test names to RFC 4648 padding rules will be confused — single-char padding (=) and double-char padding (==) are meaningfully distinct concepts.
• Impact: Misleading documentation; no runtime impact.
• Trigger: Anyone reading the test suite to understand padding behaviour.

Recommendation:

// Line 145 — change "single-char" to "double-char":
it('should produce correct double-char padding (==) for a one-byte remainder', ...)

Issue 2: Changeset bumps 8 unrelated packages

ID: changeset-overbump-unrelated-pkgs-b8f2
File: .changeset/fix-fetch-image-base64-padding.md:1
Severity: LOW
Category: maintainability

Context:

• Pattern: The changeset bumps all 9 published packages, but the only code change is in packages/core/src/utils/FetchUtil.ts (@reown/appkit-core-react-native). Packages bitcoin, coinbase, common, ethers, solana, ui, wagmi, and the root appkit-react-native have no source changes.
• Risk: Every dependent project consuming those 8 packages will see a patch bump with no actual change — adds noise to consumers' changelogs and can mask real version signals.
• Impact: Unnecessary version churn across 8 packages.
• Trigger: Any project that pins patch versions or audits changelogs.

Recommendation: Remove the 8 unrelated packages from the changeset, keeping only @reown/appkit-core-react-native: patch — unless project policy intentionally synchronises all package versions.

Breaking changes: None detected — fetchImage signature is unchanged; the new output is the correct RFC 2397 form compared to the previously malformed data URL.

[Copilot]

Pull request overview

This PR hardens FetchUtil.fetchImage data URL generation in @reown/appkit-core-react-native by normalizing content-type headers (removing semicolon-delimited parameters) and extends unit tests to cover base64 padding branches that weren’t previously exercised.

Changes:

• Strip content-type parameters (e.g., ; charset=utf-8) before building data:<type>;base64,... URLs in fetchImage.
• Add unit tests to cover _arrayBufferToBase64 padding for 1-byte (==) and 2-byte (=) remainders, plus a regression test for content-type parameter stripping.
• Add a changeset to publish patch releases across the affected packages.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
packages/core/src/utils/FetchUtil.ts	Sanitizes content-type before embedding it in a data URL returned by fetchImage.
packages/core/src/tests/utils/FetchUtil.test.ts	Adds test coverage for base64 padding and content-type parameter stripping behavior.
.changeset/fix-fetch-image-base64-padding.md	Declares patch bumps and documents the behavior change and new test coverage.

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