infra: create GitHub issues when bumping submodules to track follow-up docs changes

[marc0olo]

Problem

The current submodule bump checklist in CLAUDE.md is synchronous — it assumes the bumping agent addresses all downstream docs impact in the same PR. This breaks down in practice:

• A submodule may introduce new APIs that affect many pages across the repo
• An API may exist in one language SDK but not another yet (e.g. a JS API lands before the Rust CDK catches up)
• The bumping agent may correctly identify gaps but have no place to record them for follow-up

Concrete example that surfaced this: bumping icp-js-sdk-docs to auth v7.0.0 in PR #189 confirmed all JS/Motoko APIs, but msg_caller_info_data/msg_caller_info_signer are not yet in any released cdk-rs version. That gap has no tracking home today.

Proposal

Add a step to the "Bumping submodules" general checklist in CLAUDE.md (and AGENTS.md if applicable):

After completing the per-submodule checks, if any docs changes are identified as potentially needed but not addressed in the bump PR, open a GitHub issue with:

• Label: documentation
• Title: docs: follow-up changes needed after bumping <submodule> to <version>
• Body: a short list of what was found, what was addressed in the bump PR, and what still needs work

This turns gaps into tracked work items rather than silent omissions.

Scope

• Update the "Bumping submodules" section in CLAUDE.md
• Decide whether the issue should always be created (even if no gaps) or only when gaps exist (recommended: only when gaps exist, to avoid noise)
• Consider adding a label like submodule-bump for easy filtering, or reuse documentation + enhancement