OverClick 0.4.0

OverClick is multi-user: an admin invites an employee into one organization, and the employee works with their own token while seeing only what they created.

• Roles admin and member. The existing user becomes admin; every invited person is born a member of one organization, chosen in the invite.
• An MCP token belongs to a user and acts with that user's role and scope. Every existing token becomes the admin's, so agents keep working as before.
• Cards and missions record their author, whether created on the web or through the MCP.
• A member reaches only the cards and missions they created and the projects of their organization, on the web, the API and every MCP tool. Anything out of scope answers "not found". Aggregates (counters, progress, insights, costs) count only their cards.
• Workspace settings (harness, executors, prices, other people's tokens, invites, team) are admin-only.
• Invites: in Settings the admin creates a single-use link (email + organization, valid for 7 days). The employee signs up through /invite, then lands on /onboarding to run install.sh and pair their own token. There is no open sign-up.
• Team panel: each member shows registered → installed, with the date of their token's first use, and the admin's home shows a notice when a member finishes installing.
• OCL-226: the GitHub release webhook (/api/github/release) now requires a valid X-Hub-Signature-256 made with GITHUB_WEBHOOK_SECRET, and refuses every call when the secret is not set. Self-hosters who use the webhook must set the secret on the server and on the GitHub hook.
• Migrations 0041 (roles, token owner, authorship) and 0042 (invitation) run on boot in a single transaction.