fix(onboarding): decouple partial/indicative signals from detected — partial no longer removes a question

Fix B of the pre-#59 semantic correction. The Silent Pass had only TWO effective states though the data
carries three: a `detected` mapping (a concrete artifact) AND a `partial` mapping (an indicative signal,
e.g. a CI pipeline -> secure-development-lifecycle) both flowed through capability_ids() and were fed to
the Advisor as already-present — so a weak indication silently removed a question, exactly the Welt-1/
Welt-2 transparency we want to keep.

Now three distinct states:
  - detected   -> reduces the delta immediately (auto_detected, not asked).   [unchanged]
  - partial    -> raises assumption strength but does NOT replace the question (surfaced as `indications`,
                  the capability stays in the delta and is still asked).
  - requirement-> describes a target, never the present state (already handled by Fix A's kind split).

Changes (data + thin wiring, no new architecture):
  - SilentIntakeResult.capability_ids() returns only relationship==detected; new indicative_capability_ids()
    returns the partial ones.
  - advisor_start() gains indicative_capabilities (NOT fed into the profile) and surfaces result.indications
    = indicative ∩ required − auto_detected.
  - AdvisorResult / AdvisorResponse gain `indications` (additive, contract-safe); the service passes the
    indicative ids through.

Tests: a partial CI signal is indicative-not-detected and does NOT shrink the delta; end-to-end it appears
in `indications`, not `auto_detected`, and the gap is still asked. 28 onboarding tests pass, mypy --strict
clean on the onboarding modules, demo runs, check-loc 0. Runtime effect -> deploy + smoke.

backend-compliance/tests/test_silent_intake.py

@@ -77,3 +77,23 @@ def test_detected_capabilities_are_not_asked_again():
                         detected_capabilities=detected)
     asked = {q.capability_id for q in res.next_best_questions}
     assert "sbom_creation" not in asked and "sbom_creation" not in res.capability_delta
+
+
+def test_partial_signal_is_indicative_not_detected():
+    # a PARTIAL signal (CI present -> secure dev lifecycle) raises assumption strength but is NOT a
+    # detected capability: it must NOT shrink the delta the way a concrete artifact does.
+    res = silent_intake([IntakeSignal(source="repository", signal="github_actions_ci")], _MAP)
+    assert "secure_development_lifecycle" not in res.capability_ids()           # not counted as present
+    assert res.indicative_capability_ids() == ["secure_development_lifecycle"]  # surfaced as an indication
+
+
+def test_partial_indication_does_not_remove_the_question():
+    inp = OnboardingInput(company="x", certifications=["ISO27001"], target=["CRA"])
+    hyp = resolve_for_certifications(inp.certifications, _LIB)
+    si = silent_intake([IntakeSignal(source="repository", signal="github_actions_ci")], _MAP)
+    res = advisor_start(inp, hyp, _REQ, target_id="CRA", corpus_status={"CRA": "validated"},
+                        detected_capabilities=si.capability_ids(),
+                        indicative_capabilities=si.indicative_capability_ids())
+    assert "secure_development_lifecycle" not in res.auto_detected               # partial != detected
+    assert "secure_development_lifecycle" in res.indications                     # strength shown
+    assert "secure_development_lifecycle" in res.capability_delta                # gap still open / asked