fix(gmail): preserve rich message bodies in read

[jokrasno]

Description

Fixes #889.

Gmail +read currently falls back to the truncated snippet for HTML-only messages and can prefer a short or empty text/plain alternative over substantially richer HTML. Naive tag stripping also loses link targets, entity decoding, and block structure.

This change:

• renders HTML bodies to readable text with html2text, retaining links and document structure
• prefers rendered HTML only when it is substantially richer than a non-empty plain-text alternative
• keeps comparable valid plain text and uses the Gmail snippet only when neither body yields readable content
• adds a patch changeset and locks the new dependency

All fixtures are synthetic; no Gmail account, credentials, or real messages were used.

Validation

The five initial regressions all failed on pristine a3768d0:

0 passed; 5 failed; 701 filtered out

They cover richer multipart selection, non-truncation, anchor href preservation, HTML entity decoding, and block line breaks. The final suite also covers empty and comparable plain-text alternatives.

• cargo fmt --all -- --check
• cargo test -p google-workspace-cli test_read_ — 7 passed
• cargo test -p google-workspace-cli helpers::gmail:: — 242 passed
• cargo build --workspace
• cargo clippy --workspace -- -D warnings
• serialized workspace suite — CLI 707 passed with two unrelated, pre-existing Windows ADC tests excluded
• Changeset included

The two excluded ADC tests mutate HOME while dirs::home_dir() reads USERPROFILE on Windows; they are outside the Gmail helper and unchanged by this commit.

[changeset-bot]

🦋 Changeset detected

Latest commit: 3e25d9b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@googleworkspace/cli	Patch

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[github-actions]

This PR has been inactive for 72 hours. Closing to keep the queue clean.

[github-actions]

This PR was closed because it has been stalled for 72 hours. Feel free to magically reopen it if you want to continue working on it!

[jokrasno]

The Google CLA is now signed and the CLA check passes. The branch is still current with main and GitHub reports it mergeable. The normal author reopen operation is returning a validation error after the stale bot closed it; could a maintainer please reopen this PR? I’m ready to address review or CI feedback.