feat: implement gt sling and wisp hook system (gt-qvn7.1)

Phase 1 of tracer bullet: Slinging Handoff

- Add internal/wisp package for ephemeral work attachment
- Add gt sling command to attach work and restart
- Update gt prime to check/burn slung work on hook
- Add .beads-wisp/ to gitignore

internal/wisp/types.go

@@ -0,0 +1,131 @@
+// Package wisp provides ephemeral molecule support for Gas Town agents.
+//
+// Wisps are short-lived workflow state that lives in .beads-wisp/ and is
+// never git-tracked. They are used for:
+//   - Slung work: attaching a bead to an agent's hook for restart-and-resume
+//   - Patrol cycles: ephemeral state for continuous loops (Deacon, Witness, etc)
+//
+// Unlike regular molecules in .beads/, wisps are burned after use.
+package wisp
+
+import (
+	"time"
+)
+
+// WispType identifies the kind of wisp.
+type WispType string
+
+const (
+	// TypeSlungWork is a wisp that attaches a bead to an agent's hook.
+	// Created by `gt sling <bead-id>` and burned after pickup.
+	TypeSlungWork WispType = "slung-work"
+
+	// TypePatrolCycle is a wisp tracking patrol execution state.
+	// Used by Deacon, Witness, Refinery for their continuous loops.
+	TypePatrolCycle WispType = "patrol-cycle"
+)
+
+// WispDir is the directory name for ephemeral wisps (not git-tracked).
+const WispDir = ".beads-wisp"
+
+// HookPrefix is the filename prefix for hook files.
+const HookPrefix = "hook-"
+
+// HookSuffix is the filename suffix for hook files.
+const HookSuffix = ".json"
+
+// Wisp is the common header for all wisp types.
+type Wisp struct {
+	// Type identifies what kind of wisp this is.
+	Type WispType `json:"type"`
+
+	// CreatedAt is when the wisp was created.
+	CreatedAt time.Time `json:"created_at"`
+
+	// CreatedBy identifies who created the wisp (e.g., "crew/joe", "deacon").
+	CreatedBy string `json:"created_by"`
+}
+
+// SlungWork represents work attached to an agent's hook.
+// Created by `gt sling` and burned after the agent picks it up.
+type SlungWork struct {
+	Wisp
+
+	// BeadID is the issue/bead to work on (e.g., "gt-xxx").
+	BeadID string `json:"bead_id"`
+
+	// Context is optional additional context from the slinger.
+	Context string `json:"context,omitempty"`
+
+	// Subject is optional subject line (used in handoff mail).
+	Subject string `json:"subject,omitempty"`
+}
+
+// PatrolCycle represents the execution state of a patrol loop.
+// Used by roles that run continuous patrols (Deacon, Witness, Refinery).
+type PatrolCycle struct {
+	Wisp
+
+	// Formula is the patrol formula being executed (e.g., "mol-deacon-patrol").
+	Formula string `json:"formula"`
+
+	// CurrentStep is the ID of the step currently being executed.
+	CurrentStep string `json:"current_step"`
+
+	// StepStates tracks completion state of each step.
+	StepStates map[string]StepState `json:"step_states,omitempty"`
+
+	// CycleCount tracks how many complete cycles have been run.
+	CycleCount int `json:"cycle_count"`
+
+	// LastCycleAt is when the last complete cycle finished.
+	LastCycleAt *time.Time `json:"last_cycle_at,omitempty"`
+}
+
+// StepState represents the execution state of a single patrol step.
+type StepState struct {
+	// Status is the current status: pending, in_progress, completed, skipped.
+	Status string `json:"status"`
+
+	// StartedAt is when this step began execution.
+	StartedAt *time.Time `json:"started_at,omitempty"`
+
+	// CompletedAt is when this step finished.
+	CompletedAt *time.Time `json:"completed_at,omitempty"`
+
+	// Output is optional output from step execution.
+	Output string `json:"output,omitempty"`
+
+	// Error is set if the step failed.
+	Error string `json:"error,omitempty"`
+}
+
+// NewSlungWork creates a new slung work wisp.
+func NewSlungWork(beadID, createdBy string) *SlungWork {
+	return &SlungWork{
+		Wisp: Wisp{
+			Type:      TypeSlungWork,
+			CreatedAt: time.Now(),
+			CreatedBy: createdBy,
+		},
+		BeadID: beadID,
+	}
+}
+
+// NewPatrolCycle creates a new patrol cycle wisp.
+func NewPatrolCycle(formula, createdBy string) *PatrolCycle {
+	return &PatrolCycle{
+		Wisp: Wisp{
+			Type:      TypePatrolCycle,
+			CreatedAt: time.Now(),
+			CreatedBy: createdBy,
+		},
+		Formula:    formula,
+		StepStates: make(map[string]StepState),
+	}
+}
+
+// HookFilename returns the filename for an agent's hook file.
+func HookFilename(agent string) string {
+	return HookPrefix + agent + HookSuffix
+}