[omartelo]

Summary

Follow-up to #917. Every service method a route exposes now has the shape of the method api declares, func(context.Context, api.XOptions) (Result, error), and every route is rpc.Handle(d, api.X, s.Method). internal/routes holds no adapter closure: a service and its wire shape can no longer drift apart behind one.

• Methods that cannot fail (26, e.g. Live, Exists, Verify, Status) keep their body as an unexported method their own package calls; the exported method is the RPC shape around it.
• Callers in other packages handle the error like any other call. Where there is nowhere to return it, it is logged and the safe answer taken: relay's ticket sweep keeps the errand, the merge notice leaves the session out, the tray keeps its title, the window-failed dialog does not quit, the rage report shows its "no data" row.
• Interfaces over these services (terminal.Store, relay.Terminal, spawn.Sessions, themes.Settings, ...) and their fakes moved with them.
• terminal.spawnSession takes the StartOptions instead of ten positional arguments; godocs name opts fields instead of parameters that are gone.
• CLAUDE.md's RPC rule says the routed method has this shape.

The wire did not move: api/ and api/testdata/contract.golden are untouched, and native/ is unchanged.

Test changed

TestHandleProfilesCoverEveryProfileMethod registers typed nil services instead of a nil interface: a route now reads its method value when it is registered, which a nil interface does not have. The test assumed something the contract never promised. Every other test change follows the new signatures, no assertion loosened.

Test plan

• gofmt, go vet ./..., go test ./... (3927 passed, coverage 91.1%)
• Cross-compile and vet for linux, darwin, windows; -tags installer_e2e
• Rig on its own backend in a virtual display: window attach, session start, diff/branch footer; 50 RPC calls across every service, including a positional call refused with 400; CLI open, rename, file, rename-folder, insert, focus, theme switch, cost, close; MCP list_sessions