Report eBPFSvc, GuestProxyAgent service status, and surface eBPF/GPA … - #396

…service states

- Add Running/Transitioning/Down state classification (new ServiceRuntimeStatus.is_transitioning field, new classify_service_state helper on Windows, updated Linux map_is_active_output) instead of treating any non-Running state as a confirmed failure. Windows StartPending/ContinuePending and Linux systemd �ctivating are now classified as Transitioning rather than Error, so a service that is simply still starting up (e.g. during boot or an extension-triggered restart) no longer immediately flips the top-level extension status to Error.
- build_ebpf_substatus and build_proxy_agent_service_substatus now report the existing TRANSITIONING_STATUS instead of ERROR_STATUS for these benign transitional states, so apply_ebpf_status_override/apply_gpa_service_status_override (unchanged) naturally do not fire on them.
- Add should_force_recompute and wire it into monitor_thread so the cached eBPF/GPA-service substatus is recomputed immediately whenever the aggregate-status success/failure result changes, instead of waiting out the full ~2-minute poll interval. This prevents a stale cached Error substatus from continuing to override a just-recovered aggregate status (and vice versa for a newly-broken service) for up to 2 minutes.
- Add/extend unit tests for the new classification logic on both platforms, the Transitioning branch of both substatus builders, regression tests confirming Transitioning does not trigger either override, a test for should_force_recompute, and a backfilled test for compute_gpa_service_substatus (introduced in the previous commit without dedicated coverage).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Revert the decoupled ~2-minute polling cadence and the force-recompute-on-transition logic for the eBPF/GuestProxyAgent-service substatus checks, per manual VM testing feedback: a 2-minute-stale cache was deemed acceptable, and the added complexity to make it 'immediate' was not worth it. compute_ebpf_substatus()/compute_gpa_service_substatus() are now called fresh on every regular monitor_thread loop tick (currently 15s), same as the rest of the loop, so the status file always reflects current machine state at the cost of querying the SCM/systemctl more frequently.
- Removed should_poll, should_force_recompute, and the SERVICE_STATUS_POLL_INTERVAL_SECS constant, along with their now-orphaned unit tests.
- Refactored the override call site for readability: replaced the boolean-juggling + duplicated per-platform declarations with a single new apply_service_health_overrides helper (Windows-only) that encapsulates the eBPF-wins-priority ordering; non-Windows now calls apply_gpa_service_status_override directly. Added test_apply_service_health_overrides_priority covering all three priority outcomes.
- Kept the Running/Transitioning/Down state classification (is_transitioning, classify_service_state, TRANSITIONING_STATUS branches) from the prior code-review fix, since it addresses a separate, still-valid concern (avoiding false-positive Error while a service is merely mid-boot/mid-restart) unrelated to polling cadence.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

… code

- Consolidate apply_ebpf_status_override and apply_gpa_service_status_override, which were
  identical apart from which SubStatus they read, into one apply_sub_status_override_in_error
  function used by both call sites (per review feedback: 'apply_gpa_service_status_override is
  the same as apply_ebpf_status_override... suggest keeping one').
- Replace map_is_active_output's (bool, bool, String) tuple return with a named ActiveState
  struct, so each field is self-documenting at call sites (per review feedback: 'you are going
  to kill me with this 3 (bool, bool, string), it is hard to maintain').
- Extract a shared combined_service_health helper encapsulating the Success/Error/Transitioning
  decision rule that build_ebpf_substatus (3 services) and build_proxy_agent_service_substatus
  (1 service) had each implemented separately, removing ~35 duplicated lines and centralizing
  the rule in one tested place.
- Simplify query_service_run_status to delegate to the pre-existing check_service_status
  function instead of re-implementing the same SCM query_service_status/query_service_config
  lookup a second time, removing ~20 duplicated lines.
- Add test_combined_service_health and update existing tests for the ActiveState struct.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Comment-only change: trimmed 12 doc/inline comment blocks (ranging 4-14 lines) that were
added in the preceding commits down to 2-3 lines each, keeping only the essential what/why.
No code or logic was changed.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>