fix(whatsapp): load group allowlist from profile env

[thisisandreeeee]

Summary

• fall back to profile-scoped WHATSAPP_GROUP_ALLOWED_USERS when no group allowlist key is present in PlatformConfig.extra
• preserve explicit snake_case/camelCase config precedence, including an intentionally empty list
• add coverage for environment fallback, explicit config precedence, and explicit-empty fail-closed behavior

Root cause

The Baileys bridge and Python adapter enforce separate inbound gates. Legacy/setup-created configurations may provide group JIDs through WHATSAPP_GROUP_ALLOWED_USERS; unlike the DM path, adapter construction only read group_allow_from / groupAllowFrom from config.extra. After a gateway restart, group_policy: allowlist could therefore start with an empty Python-side group allowlist even though the documented profile environment contained valid groups.

This mirrors the existing DM resolution contract and uses _wenv so multiplexed profiles remain isolated.

Verification

• tests/gateway/test_whatsapp_group_gating.py: 13 passed
• relevant tests/gateway/test_pairing_allowlist_bypass.py DM precedence cases: 4 passed
• git diff --check

[spfcraze]

This was generated by AI during triage.

A note on overlap:

This PR and open PR #61924 change the same _group_allow_from resolution in plugins/platforms/whatsapp/adapter.py, with the same precedence — explicit config key first, then a WHATSAPP_GROUP_ALLOWED_USERS fallback.

#61924 also rewrote the DM allow_from line; that DM env fallback has since landed on main, so the overlap left between the two PRs is the group half this PR carries.

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Checked against 78393b7 — the tip of fix/whatsapp-adapter-env-allowlist when this was written — and 1be70d6, main at the same moment.

[alt-glitch]

This was generated by AI during triage.

Related to #61924: this focused group-allowlist fallback uses the same explicit-config precedence, while #61924 covers both DM and group allowlists.

[kshitijk4poor]

Fixed on main via #115360 (merge 8925c70a1c): the adapter's group list now falls back to the profile-scoped WHATSAPP_GROUP_ALLOWED_USERS (_wenv) exactly as this PR proposed. Earlier submissions of the same fix: #37452 @AhmetArif0, #61924 @iborazzi. Closing as fixed on main; thanks.