P3.1: Add ExecutionMode/OverlapPolicy to Config; add Pending to JobRuntime

Introduces ExecutionMode (parallel/sequential) and OverlapPolicy
(skip/queue) types and constants in domain/config.go, wires defaults
(parallel/skip) into loadOrCreateConfig and the normalization pass, and
adds validation in validateConfig. Adds Pending bool to JobRuntime as
the flag P3.3 will use to re-run a queued overlap. Marks P3.1 done.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/PRE-RELEASE-TASKS.md

@@ -94,7 +94,7 @@ These land together because both edit `domain/job.go` and `storage/store.go`.
 - [x] P2.4 — `.gitignore` / `.dockerignore`
 
 ### Phase 3 — Task-queue model + settings
-- [ ] P3.1 — Config/runtime fields + defaults
+- [x] P3.1 — Config/runtime fields + defaults
 - [ ] P3.2 — Split dispatch into `app/run.go`
 - [ ] P3.3 — Rework `RunDue`/`executeRun` for mode + overlap policy
 - [ ] P3.4 — Settings Queue selects

src/app/operations.go

@@ -476,5 +476,11 @@ func validateConfig(config domain.Config) error {
 	if config.MaxLogAgeDays <= 0 {
 		return errors.New("max log age days must be a positive number")
 	}
+	if config.ExecutionMode != domain.ExecutionModeParallel && config.ExecutionMode != domain.ExecutionModeSequential {
+		return errors.New("execution mode must be 'parallel' or 'sequential'")
+	}
+	if config.OverlapPolicy != domain.OverlapPolicySkip && config.OverlapPolicy != domain.OverlapPolicyQueue {
+		return errors.New("overlap policy must be 'skip' or 'queue'")
+	}
 	return nil
 }

src/app/operations_test.go

@@ -25,7 +25,7 @@ func newTempService(t *testing.T, jobs []domain.Job) *Service {
 			JobsPath:       filepath.Join(dir, "jobs.json"),
 			LogsDir:        filepath.Join(dir, "logs"),
 		},
-		Config: domain.Config{JobsDir: ".", LogsDir: "logs", MaxLogFiles: 100, MaxLogAgeDays: 30},
+		Config: domain.Config{JobsDir: ".", LogsDir: "logs", MaxLogFiles: 100, MaxLogAgeDays: 30, ExecutionMode: domain.ExecutionModeParallel, OverlapPolicy: domain.OverlapPolicySkip},
 	}
 	return NewService(store, jobs)
 }

src/domain/config.go

@@ -5,6 +5,28 @@ package domain
 // launches omit this flag and open the normal window.
 const StartInTrayArgument = "--start-in-tray"
 
+// ExecutionMode controls whether due jobs run concurrently or one at a time.
+type ExecutionMode string
+
+const (
+	// ExecutionModeParallel allows all due jobs to start simultaneously.
+	ExecutionModeParallel ExecutionMode = "parallel"
+	// ExecutionModeSequential runs due jobs one after another, in order.
+	ExecutionModeSequential ExecutionMode = "sequential"
+)
+
+// OverlapPolicy decides what happens when a job's next run fires while the
+// previous run is still active.
+type OverlapPolicy string
+
+const (
+	// OverlapPolicySkip discards the new run when the job is already running.
+	OverlapPolicySkip OverlapPolicy = "skip"
+	// OverlapPolicyQueue holds the new run and starts it as soon as the current
+	// run finishes.
+	OverlapPolicyQueue OverlapPolicy = "queue"
+)
+
 // Config is stored in gosentry.json next to the program. It contains only
 // application-level choices: where to read jobs from, where to write logs, and
 // how the desktop shell should behave.
@@ -16,6 +38,8 @@ type Config struct {
 	StartOnLogin      bool          `json:"start_on_login,omitempty"`
 	KeepRunningInTray bool          `json:"keep_running_in_tray,omitempty"`
 	NotifyOnFailure   bool          `json:"notify_on_failure,omitempty"`
+	ExecutionMode     ExecutionMode `json:"execution_mode,omitempty"`
+	OverlapPolicy     OverlapPolicy `json:"overlap_policy,omitempty"`
 }
 
 // JobsFile is the on-disk shape of jobs.json. Wrapping the slice in a top-level

src/domain/runtime.go

@@ -18,6 +18,10 @@ type JobRuntime struct {
 	// scheduler comparisons. NextRun above is its formatted display string and is
 	// the only form shown in the GUI.
 	NextDue time.Time
+
+	// Pending is set when a run was skipped due to the overlap policy being
+	// "queue". The scheduler will start this job as soon as the current run ends.
+	Pending bool
 }
 
 // NewRuntime builds the initial runtime state for a freshly loaded or created

src/storage/store.go

@@ -31,6 +31,8 @@ type yamlConfig struct {
 	StartOnLogin      bool                `yaml:"start_on_login,omitempty"`
 	KeepRunningInTray bool                `yaml:"keep_running_in_tray,omitempty"`
 	NotifyOnFailure   bool                `yaml:"notify_on_failure,omitempty"`
+	ExecutionMode     domain.ExecutionMode `yaml:"execution_mode,omitempty"`
+	OverlapPolicy     domain.OverlapPolicy `yaml:"overlap_policy,omitempty"`
 }
 
 type yamlJob struct {
@@ -108,6 +110,8 @@ func loadOrCreateConfig(paths Paths) (domain.Config, error) {
 		StartOnLogin:      false,
 		KeepRunningInTray: true,
 		NotifyOnFailure:   true,
+		ExecutionMode:     domain.ExecutionModeParallel,
+		OverlapPolicy:     domain.OverlapPolicySkip,
 	}
 
 	if _, err := os.Stat(paths.ConfigPath); errors.Is(err, os.ErrNotExist) {
@@ -147,6 +151,12 @@ func loadOrCreateConfig(paths Paths) (domain.Config, error) {
 	if config.MaxLogAgeDays <= 0 {
 		config.MaxLogAgeDays = 30
 	}
+	if config.ExecutionMode == "" {
+		config.ExecutionMode = domain.ExecutionModeParallel
+	}
+	if config.OverlapPolicy == "" {
+		config.OverlapPolicy = domain.OverlapPolicySkip
+	}
 	return config, nil
 }