canonical(frontend): autobot-frontend has SLM-control-plane calls (getSLMUrl) with no dedicated client — need an SLM bridge analogous to slmApiClient #12614

Discovered during #12363 Phase 2 (PR #12613). Two main-frontend composables — composables/useHostInventory.ts and composables/useTLSCredentials.ts — issue raw fetch() against the SLM control-plane backend via getSLMUrl(), NOT the app backend. They were correctly excluded from the ApiClient/fetchWithAuth migration because the app-scoped bridge would inject the wrong base URL + app JWT/org headers (the SLM backend has its own token lifecycle).

Gap: autobot-frontend has no canonical client for its SLM-targeting calls (unlike autobot-slm-frontend which now has slmApiClient). These calls stay on raw fetch until a dedicated main-frontend SLM bridge exists.

Proposed: a small slmFetch/SlmApiClient in autobot-frontend that resolves getSLMUrl() + injects the SLM token, then migrate useHostInventory + useTLSCredentials (and any other getSLMUrl callers — grep) onto it. Refs #12363, #12420.