docs(legal): cover ThingsBoard Edge 4.4 under BUSL in the legal set

[volodymyr-babak]

What

ThingsBoard Edge 4.4 merges Edge CE and Edge PE into one project under BUSL-1.1, with an Additional Use Grant of its own.

• Production use is free for an Edge registered to a licensed ThingsBoard server.
• The Edge itself has no device limit; the server's license key limits Edges and Devices.

This PR brings the legal pages in line with that, ready for legal review. Merge together with the Edge 4.4 release, not before.

New page: /legal/busl-edge/. It reproduces the Edge LICENSE and gets an OG card entry. Matching LICENSE change: MazurenkoNick/edge-rehearsal#1. The grant text in both is verified identical.

• (a) and (b) are word for word as in /legal/busl/. Platform code copied into Edge (about 5,000 BUSL files) can therefore never get looser terms than in the platform repo.
• (c) is new: an Edge Instance registered to a ThingsBoard Server whose production use is licensed.
• (i) has a branding exception and (ii) uses the server's key.

License Agreement

• Software: now includes ThingsBoard Edge (thingsboard-edge).
• New definitions: Edge and Edge count. LICENSE file now covers both repositories.
• Edges are not instances or deployments: an Edge is not a Production Instance (otherwise Pilot's single instance would be used up by the first Edge). In 5.1, an Edge registered in your deployment is part of it, needs no Key, and is not a second deployment.
• Device: an Edge is never a Device, because it is not a device entity and is counted separately as the Edge count. A gateway is still a Device only as to data it originates. Devices behind an Edge count toward the deployment the Edge is registered in.
• Limits (5.2, 5.3): registering Edges beyond the limit is refused. Existing Edges are never disconnected.
• Expiry (4.6): no Edge-specific text. Upstream's 4.6 (Subscription / Perpetual) is kept as is: after expiry a deployment can continue on a no-charge key, whose Edge allowance is in the Terms of Use table below.

Terms of Use

• Edges per key category (section 3):

  Key	Edges
  Free (Commercial no-charge)	1
  Non-commercial	3
  Development	unlimited, non-production only
  Community Grant	per Grant Record
  Paid	per Order

  These match the portal plans and licence-server plan data.

• Section 4: Edges on a Development-key or keyless server are non-production. An Edge in production needs the server to hold a production key.

• Section 5: the Development key's unlimited count covers Edges too.

Community Grant License Agreement

• 1.1 / 1.2: Edge CE is unified the same way, and Edge CE releases before 4.4 stay Apache 2.0.
• Registered Edges defined.
• 4.3: Edges = Registered Edges, minimum 1. This matches licence-server provisioning: 1 included plus registered − 1 as bonus, with the Edge count taken from the Instance Check Report.

Privacy Policy: Edge instances perform the release update check themselves. Edge's DefaultUpdateService sends platform, version and instance ID.

Pricing page: the Edge and Trendz add-on cards said "from $7" and "from $12". They now say $19 and $29, as in Appendix A, the plan calculator and the portal.

Source-available blog FAQ: upstream already answers "Edge — yes". This PR corrects "the same license as the platform" to the Business Source License with an Additional Use Grant of its own, and links /legal/busl-edge/.

Merged with upstream main (incl. #775, legal texts of 16 October 2026, and #724, perpetual Trendz pricing). Conflicts resolved:

• Terms of Use intro: this PR's wording, pointing to both LICENSE files.
• License Agreement 4.6: upstream's text; this PR's Edge line is dropped.
• Appendix A: upstream's text. Its Trendz pricing and Update Fee examples already match what this PR proposed, so they are no longer in this diff.
• Blog FAQ: upstream's text, with the change above.

Open for legal / product

• Revision Date stays at upstream's October 16, 2026. Decide whether the Edge changes ship under that revision or get a new date. Under 13.5, changes apply to existing subscribers only from renewal with 30 days' notice, and never to perpetual licences. Decide whether the Edge points are framed as clarifications.
• Customer-operated Edges: may an Edge registered to your deployment run at a site another legal entity operates? Clauses 2.1 and 3 still bar another entity operating "its own deployment" under your key. The new wording is neutral on where an Edge runs.
• Upgrading from Free to Pilot loses the Edge: Free includes 1 Edge, but paid plans include none without the Edge Computing add-on (Pilot +$19).
• Community Grant package extras: it also provisions 1 Remote Agent and 5M AI credits. The agreement grants neither (License Agreement 2.7: nothing included unless stated).
• Licence-server bootstrap still prices perpetual Trendz at $1,499 + $0.30 per device (CommunityGrantPlanBootstrap.java:85-91). The live portal data shows $8,000.

Verification

• Prettier: clean on the changed MDX. marketing-meta.ts and tb-self-managed.ts were already non-conforming before this change.
• ESLint: clean on the changed TS.
• Grant text: the /legal/busl-edge/ grant was compared mechanically with the Edge LICENSE grant, and they are identical.
• After the merge: no conflict markers remain, and the diff against upstream main contains only this PR's Edge changes.
• Not run: build, linkcheck and landmarks. Prettier and ESLint were not re-run after the merge.