fix(test): resolve nil-pointer panic in TestCommandSide_ChangeUserHuman (#11695)

# Which Problems Are Solved

1. `nx run @zitadel/api:test-unit` panics in
`TestCommandSide_ChangeUserHuman` due to two test cases (added in
0261536) missing the required `loginPaths` field. Since the field type
is `func(*testing.T) LoginPaths`, its zero value is `nil`, and calling
it causes a SIGSEGV.

2. Three targets in `apps/api/project.json` (`test-unit`, `build`,
`build-linux`) were silently non-cacheable because NX does not merge
`cache: true` from `targetDefaults` when a project-level target
overrides other properties like `dependsOn` or `inputs`.

3. `TestServer_AuthorizeOrDenyDeviceAuthorization` integration test is
flaky — it uses hardcoded `5*time.Second` timeouts for `EventuallyWithT`
polling, while the rest of the file uses
`WaitForAndTickWithMaxDuration(ctx, time.Minute)`. Under CI load, 5
seconds is insufficient and the empty ID cascades into a validation
error.

# How the Problems Are Solved

**Test panic fix:**
- Added missing `loginPaths: expectLoginPathsNoCall` to both broken test
cases ("change human email verified (self-management), not allowed" and
"change human phone verified (self-management), not allowed").

**NX cache fix:**
- Added explicit `"cache": true` to `test-unit`, `build`, and
`build-linux` targets in `apps/api/project.json`.
- Verified with `pnpm nx show project @zitadel/api --json` that all
three targets now resolve with `cache: true`.

**Integration test flakiness fix:**
- Replaced all 6 hardcoded `assert.EventuallyWithT(t, ...,
5*time.Second, 100*time.Millisecond)` calls in
`TestServer_AuthorizeOrDenyDeviceAuthorization` with
`require.EventuallyWithT(t, ..., retryDuration, tick)` using
`integration.WaitForAndTickWithMaxDuration(CTXLoginClient,
time.Minute)`.
- Changed from `assert` (non-fatal) to `require` (fatal) so timeout
failures stop the test immediately instead of cascading with empty IDs.

# Additional Context

- The broken unit test landed on main because CI skips `lint_test_build`
on pushes to main (`if: github.ref != 'refs/heads/main'`). A follow-up
issue was created: #11696.
- The integration test flakiness was missed by the previous fix in
#10752.

---------

Co-authored-by: Copilot <[email protected]>
Co-authored-by: Livio Spring <[email protected]>

apps/api/project.json

@@ -66,6 +66,7 @@
                 "generate",
                 "build-console"
             ],
+            "cache": true,
             "command": "bash -c 'CGO_ENABLED=0 go build -o .artifacts/bin/$(go env GOOS)/$(go env GOARCH)/zitadel.local -ldflags=\"-s -w\"'",
             "inputs": [
                 {
@@ -89,6 +90,7 @@
                 "generate",
                 "build-console"
             ],
+            "cache": true,
             "command": "bash -c 'CGO_ENABLED=0 GOOS=linux go build -o .artifacts/bin/linux/$(go env GOARCH)/zitadel.local -ldflags=\"-s -w\"'",
             "inputs": [
                 {
@@ -161,6 +163,7 @@
             "dependsOn": [
                 "generate"
             ],
+            "cache": true,
             "command": "go test -race -coverprofile=profile.api.test-unit.cov -coverpkg=./internal/...,./backend/...  ./...",
             "inputs": [
                 "sources",