refactor(decide): split type definitions into types.go; clarify detecting helper

Address PR review (aa-1):
- Move the decider input/output type definitions (LifecycleDecision,
  ProbeInput, ProcessLiveness, OpenPRInput, DetectingInput) out of the
  execution file into a dedicated types.go, leaving decide.go for behaviour.
- Expand the detecting() helper doc to spell out that it adapts a probe
  verdict into the shared CreateDetectingDecision anti-flap path so each
  probe branch doesn't re-implement the quarantine counter.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/internal/domain/decide/decide.go

@@ -23,65 +23,6 @@ const (
 	DetectingMaxDuration = 5 * time.Minute
 )
 
-// LifecycleDecision is the output of every decider: the derived display status
-// plus the canonical sub-state values to persist, the human-readable evidence,
-// and the (possibly updated) detecting memory.
-type LifecycleDecision struct {
-	Status        domain.SessionStatus
-	Evidence      string
-	Detecting     *domain.DetectingState
-	SessionState  domain.SessionState
-	SessionReason domain.SessionReason
-	PRState       domain.PRState
-	PRReason      domain.PRReason
-}
-
-// ProbeInput reconciles runtime + process liveness. A *failed* probe (timeout
-// or error) is distinct from a "dead" verdict and must route to detecting,
-// never to a death conclusion. KillRequested short-circuits to terminal.
-type ProbeInput struct {
-	Runtime        domain.RuntimeState
-	RuntimeFailed  bool
-	Process        ProcessLiveness
-	ProcessFailed  bool
-	RecentActivity bool
-	KillRequested  bool
-	Prior          *domain.DetectingState
-	Now            time.Time
-}
-
-// ProcessLiveness mirrors isProcessRunning's three-valued answer.
-type ProcessLiveness string
-
-const (
-	ProcessAlive         ProcessLiveness = "alive"
-	ProcessDead          ProcessLiveness = "dead"
-	ProcessIndeterminate ProcessLiveness = "indeterminate"
-)
-
-// OpenPRInput drives the PR pipeline ladder for an open PR.
-type OpenPRInput struct {
-	CIFailing        bool
-	ChangesRequested bool
-	Approved         bool
-	Mergeable        bool
-	ReviewPending    bool
-	IdleBeyond       bool // idle past the stuck threshold
-	Number           int
-	URL              string
-}
-
-// DetectingInput feeds the quarantine counter. Evidence is hashed with
-// timestamps stripped, so "same ambiguous signal" keeps the counter climbing
-// while any real change resets it.
-type DetectingInput struct {
-	Evidence       string
-	ProposedState  domain.SessionState
-	ProposedReason domain.SessionReason
-	Prior          *domain.DetectingState
-	Now            time.Time
-}
-
 // ResolveProbeDecision reconciles runtime/process liveness into a decision.
 //
 // The ordering encodes the load-bearing invariants:
@@ -285,9 +226,11 @@ var timestampPatterns = []*regexp.Regexp{
 	regexp.MustCompile(`\b\d{10,13}\b`),
 }
 
-// detecting builds a quarantine decision from a probe verdict, threading the
-// prior counter through CreateDetectingDecision so probe ambiguity is subject
-// to the same anti-flap escalation as any other detecting cause.
+// detecting adapts a probe verdict into the shared anti-flap path. It packages
+// the proposed reason + evidence (plus the prior counter from the same probe
+// input) into a DetectingInput and defers to CreateDetectingDecision, so every
+// probe-driven ambiguity is counted and escalated by the identical quarantine
+// logic instead of each probe branch re-implementing the counter.
 func detecting(in ProbeInput, reason domain.SessionReason, evidence string) LifecycleDecision {
 	return CreateDetectingDecision(DetectingInput{
 		Evidence:       evidence,

backend/internal/domain/decide/types.go

@@ -0,0 +1,66 @@
+package decide
+
+import (
+	"time"
+
+	"github.com/aoagents/agent-orchestrator/backend/internal/domain"
+)
+
+// LifecycleDecision is the output of every decider: the derived display status
+// plus the canonical sub-state values to persist, the human-readable evidence,
+// and the (possibly updated) detecting memory.
+type LifecycleDecision struct {
+	Status        domain.SessionStatus
+	Evidence      string
+	Detecting     *domain.DetectingState
+	SessionState  domain.SessionState
+	SessionReason domain.SessionReason
+	PRState       domain.PRState
+	PRReason      domain.PRReason
+}
+
+// ProbeInput reconciles runtime + process liveness. A *failed* probe (timeout
+// or error) is distinct from a "dead" verdict and must route to detecting,
+// never to a death conclusion. KillRequested short-circuits to terminal.
+type ProbeInput struct {
+	Runtime        domain.RuntimeState
+	RuntimeFailed  bool
+	Process        ProcessLiveness
+	ProcessFailed  bool
+	RecentActivity bool
+	KillRequested  bool
+	Prior          *domain.DetectingState
+	Now            time.Time
+}
+
+// ProcessLiveness mirrors isProcessRunning's three-valued answer.
+type ProcessLiveness string
+
+const (
+	ProcessAlive         ProcessLiveness = "alive"
+	ProcessDead          ProcessLiveness = "dead"
+	ProcessIndeterminate ProcessLiveness = "indeterminate"
+)
+
+// OpenPRInput drives the PR pipeline ladder for an open PR.
+type OpenPRInput struct {
+	CIFailing        bool
+	ChangesRequested bool
+	Approved         bool
+	Mergeable        bool
+	ReviewPending    bool
+	IdleBeyond       bool // idle past the stuck threshold
+	Number           int
+	URL              string
+}
+
+// DetectingInput feeds the quarantine counter. Evidence is hashed with
+// timestamps stripped, so "same ambiguous signal" keeps the counter climbing
+// while any real change resets it.
+type DetectingInput struct {
+	Evidence       string
+	ProposedState  domain.SessionState
+	ProposedReason domain.SessionReason
+	Prior          *domain.DetectingState
+	Now            time.Time
+}