[Website] Discoverability, migration, and documentation quality roadmap

## Goal

Make the official Apache BifroMQ (Incubating) website and documentation easier for users and contributors to find and use, complete the migration from `bifromq.io`, and establish reliable measurement on the canonical hostname.

The work focuses on user success, accurate documentation, and sustainable project growth. Changes receive normal public review, with the website-readiness record maintained in #71.

## Current snapshot (2026-08-21)

- The canonical site is `https://bifromq.apache.org/`.
- The intentional indexable sitemap contains 124 canonical URLs instead of the pre-rollout 412 URLs.
- Current documentation and 3.3.x historical documentation are indexable; 3.2.x and older pages remain accessible with archived labels and `noindex`.
- The canonical Google Search Console property is owner-verified and the sitemap has 0 warnings and 0 errors.
- ASF-hosted Matomo site ID 90 is deployed with the official cookieless/DoNotTrack configuration through #84 and #85.
- Valuable `bifromq.io` URLs now reach a relevant 200 destination in at most one redirect; unknown removed paths return 410.
- Shared ASF identity, metadata, canonical, robots, structured-data, social-preview, and generated-site CI checks are deployed.
- The live DOAP file is valid but is not yet registered in the ASF projects feed.

Third-party modelled data was used only to identify investigation areas. Success is evaluated with first-party webmaster/analytics data and community feedback.

## Discovery themes

In addition to branded searches, improve useful coverage for intent such as:

- `Apache MQTT broker` and `Apache MQTT`;
- open-source, distributed, and multi-tenant MQTT broker;
- high-concurrency MQTT deployment and Linux tuning; and
- MQTT broker architecture, operations, observability, and selection.

These phrases describe user intent, not an alternate project name. Published content uses the correct project name, Apache BifroMQ, and answers the underlying questions naturally.

## Workstreams

- [x] #67 — GSC and ASF Matomo implementation are complete, and the accepted 14-day GSC baseline is recorded.
- [x] #68 — live legacy URL repair is complete, and ASF ownership of the domain is confirmed.
- [x] #69 — the current English-only documentation scope and legacy localized URL handling are recorded.
- [x] #70 — policy and Development noindex regression fix are deployed; the accepted search baseline is recorded in #67.
- [x] #71 — website readiness review is complete; remaining content-review and DOAP work is independently tracked in #72 and #88.
- [ ] #72 — implementation is in ready-for-review PR #86 with `@popduke` formally requested as reviewer.
- [x] #73 — the existing-page implementation merged and deployed through #87; its initial search baseline is recorded in #67.

## Scope decisions and dependencies

- #67 establishes canonical GSC monitoring and ASF-hosted Matomo.
- Bing Webmaster Tools is explicitly deferred from this iteration and is not a #67 or roadmap closure criterion. Revisit it when the project has an ASF/project-owned access and recovery path.
- #70 defines which versioned pages are intentionally indexable; its technical policy is deployed.
- #71 records the completed readiness review; ASF ownership of the legacy domain is confirmed, with technical migration evidence in #68.
- #72 can receive technical review now; #73 implementation is complete, with its initial search baseline recorded in #67.

## Definition of done

- [ ] Each child issue is complete or has a documented community decision.
- [x] GSC verifies the canonical hostname and the sitemap has no sitemap-level errors.
- [x] ASF-hosted Matomo reports aggregate site usage with the approved privacy configuration.
- [x] Current owner access is recorded; long-term access and recovery documentation is classified as ongoing governance rather than an iteration closure criterion.
- [x] Valuable legacy URLs reach a relevant 200 destination or an intentional 410.
- [x] Legacy-domain ASF ownership is confirmed, with redirect and intentional 410 evidence recorded in #68.
- [x] Sitemap membership matches the approved version and localization policy.
- [ ] Linux tuning guidance is reviewed, merged, and deployed through #72; MQTT selection measurement is represented in the #67 baseline.
- [x] #71 completed the readiness review and assigned independent follow-ups to dedicated issues.
- [x] A complete 14-day GSC baseline is recorded with clearly labelled metrics; longer-term reporting is ongoing operations.

Keep this roadmap open until the remaining work in #72 and #88 is complete or has a documented community decision.

Start by reading the remaining work in #72 and #88, then compare it with the monitoring baseline in #67 and the readiness record in #71. The roadmap is done when those follow-ups are complete or have documented community decisions, with Linux tuning guidance reviewed, merged, and deployed.

Written by the indexing model from the issue text.