Add WattWächter Plus integration docs

[smartcircuits]

Proposed change

Add documentation for the new WattWächter Plus integration. The WattWächter Plus is a local energy monitoring device that reads smart meter data via SML/OBIS and exposes it over a local HTTP API.

Type of change

• Spelling, grammar or other readability improvements (current branch).
• Adjusted missing or incorrect information in the current documentation (current branch).
• Added documentation for a new integration I'm adding to Home Assistant (next branch).
  • Brand assets are included in the integration directory (no separate brands PR needed since 2026.03).
• Added documentation for a new feature I'm adding to Home Assistant (next branch).
• Removed stale or deprecated documentation.

Additional information

• Link to parent pull request in the codebase: Add WattWächter Plus integration core#165238
• Link to parent pull request in the Brands repository: Add WattWächter Plus brand assets brands#10065
• This PR fixes or closes issue:

Checklist

• This PR uses the correct branch, based on one of the following:
  • I made a change that is related to an upcoming version of Home Assistant and used the next branch.
• The documentation follows the Home Assistant documentation standards.

[home-assistant]

It seems that this PR is targeted against an incorrect branch since it has a parent PR on one of our codebases. Documentation that needs to be updated for an upcoming release should target the next branch. Please change the target branch of this PR to next and rebase if needed.

[netlify]

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[Copilot]

Pull request overview

Adds a new integration documentation page for the upcoming WattWächter Plus integration, describing setup, supported entities, options, troubleshooting, and examples for Home Assistant users.

Changes:

• Introduces a new source/_integrations/wattwaechter.markdown integration doc page with prerequisites, config flow info, and supported functionality.
• Documents options (polling interval), firmware update behavior, and troubleshooting steps.
• Adds an example automation and Energy dashboard guidance.

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[c0ffeeca7]

Thank you for contributing, @smartcircuits 💪

1. As this PR seems to be related to a code PR, please rebase and point this PR against the next branch.
2. Please restore the original PR templatae
3. In the PR template, add the link to the related brands PR.

If you do not want to rebase, another method to resolve this is to do the following:

1. Close this PR.
2. Switch to the next branch, and pull the latest changes from next.
3. Create your branch from there, add your changes, and push them to GH against the next branch.
4. Restore the original PR template.
5. In the PR template, add the link to the related brands PR.

[c0ffeeca7]

I'm drafting this PR, as changes are needed.

Please undraft it once the changes have been implemented and the PR is ready for review again.

[smartcircuits]

Thanks for the review! Here's what I've done:

1. Rebased onto next branch and updated the PR target.
2. Restored the PR template with all required fields.
3. Brand assets are included in the integration directory in the core PR (no separate brands PR needed since 2026.03).
4. Fixed ha_release to 2026.4.
5. Applied Copilot suggestions (table → list, "e.g." → "for example", YAML line length, system info wording).

The Netlify deploy preview fails — I believe this is because this is my first contribution and Netlify doesn't build previews for untrusted forks. The Lint Markdown and Lint Text checks both pass.

Core PR: home-assistant/core#165238

[smartcircuits]

Thanks for the fix! I didn't realize mDNS/zeroconf weren't in the glossary — that explains the Netlify build failures. All checks are green now.

[smartcircuits]

Hi @c0ffeeca7, just a friendly ping — I've addressed all the requested changes (rebased to next, restored PR template, fixed the glossary term). Is there anything else needed from my side?

[c0ffeeca7]

style tweaks

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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