test: add e2e coverage and mock backends for jira and linear integrations (#771)

* test: add e2e coverage and mock backends for jira and linear integrations

Adds in-memory MockClient + MockController for both integrations gated by
KANDEV_MOCK_{JIRA,LINEAR}=true, plus apiClient mock helpers and Playwright
specs covering settings and import flows.

Also fixes ValidatedPopover's TriggerButton silently dropping radix Slot's
onClick handler — the popover wouldn't open under any synthetic-click path
(including Playwright). Spreads `...rest` onto the inner Button.

Reworks the integration cleanup hook in test-base as an auto fixture so it
runs for every test using the imported `test` object, not just tests in the
fixture file itself.

* fix: address PR review feedback on jira/linear mocks and e2e specs

- Fix SetAuthResult docstrings: nil simulates an unconfigured state, not the default success.
- Drop unused JSON tags from doneTransitionCall and setStateCall (Go-only test fixtures).
- Track Linear issue insertion order so SearchIssues returns deterministic results instead of map-iteration shuffle.
- Document filterByJQL precedence at the SearchTickets call site so the all-hits-on-no-match fallback is visible.
- Wait for the post-save auth-health probe before forcing a failure in the seeded-failure tests, eliminating a goroutine race.
- Reorder authMethod precedence in setJiraConfig/setLinearConfig to put the spread first so 'caller wins' reads naturally.

---------

Co-authored-by: Kandev Agent <agent@kandev.dev>

AGENTS.md

@@ -336,6 +336,7 @@ Jira and Linear are the model: per-workspace credentials, a 90s auth-health poll
 - Use `internal/integrations/secretadapter` instead of writing your own upsert wrapper around `secrets.SecretStore`. The adapter satisfies any per-integration `SecretStore` interface shaped as `{Reveal, Set, Delete, Exists}`.
 - Use `internal/integrations/healthpoll` for the auth-health loop. Implement the `Prober` interface (`ListConfiguredWorkspaces` + `RecordAuthHealth`) on a small adapter and let `healthpoll.New("name", prober, log)` own Start/Stop/ticker. Keep integration-specific loops (JQL polling, webhook reconciliation, etc.) separate, like jira's issue-watch loop.
 - Wire the service via a per-domain `init<Name>Service(...)` helper in `cmd/kandev/services.go`, not inline in `provideServices`.
+- Ship a `mock_client.go` + `mock_controller.go` next to the real client. `Provide` branches on `KANDEV_MOCK_<NAME>=true` and returns the in-memory client; `RegisterMockRoutes(router, svc, log)` mounts `/api/v1/<name>/mock/*` only when the service was built with the mock. The e2e backend fixture sets the env var so Playwright tests drive the mock via `apiClient.mock<Name>*()` helpers — see jira/linear for the layout.
 
 **Frontend**:
 - Hooks live under `hooks/domains/<name>/`, **not** `components/<name>/`.
@@ -357,4 +358,4 @@ This file is read by AI coding agents (Claude Code via `CLAUDE.md` symlink, Code
 
 ---
 
-**Last Updated**: 2026-05-01
+**Last Updated**: 2026-05-02