v1.1.1: fw_version heartbeat reports plain SemVer

Patch release: correct the firmware version reported in the device heartbeat.

Fixes

• The /status heartbeat now reports fw_version as plain SemVer with no leading v (tag v1.1.1 reports 1.1.1). Release builds previously baked the raw tag into FW_VERSION, producing a leading v. This lets the Tesserae server compare the running build against the latest available for its firmware update check.
• Fixes a related double v in the provisioning portal footer.

Notes

• No device behaviour, protocol, panel, or button changes.
• Artifact and catalog paths are unchanged (they keep the v prefix); only the compiled-in FW_VERSION string changed.
• Documents the fw_version heartbeat field and its format in the README.

All eight targets build and publish to the browser flasher.