feat: docker-compose stacks with Forge-themed UI

Adds a new Stacks feature: upload/edit docker-compose YAML,
deploy as atomic units, browse revisions, roll back, and
stream logs. Backend in internal/stack + internal/api/stacks.go,
persistent storage in internal/store/stacks.go.

Stacks pages (list, new, detail) use a modern Forge aesthetic —
Instrument Serif display type, JetBrains Mono for meta/code,
indigo ember accents, dot-grid hero, registration marks on
hover, terminal panel for logs. Palette is sourced from the
app's existing design tokens so the feature remains consistent
with the rest of Tinyforge.

Fonts self-hosted via @fontsource/instrument-serif and
@fontsource/jetbrains-mono to satisfy the strict CSP.

internal/store/models.go

@@ -234,6 +234,44 @@ type StaticSiteSecret struct {
 	UpdatedAt string `json:"updated_at"`
 }
 
+// Stack represents a docker-compose stack managed as a single deployable unit.
+type Stack struct {
+	ID                 string `json:"id"`
+	Name               string `json:"name"`
+	Description        string `json:"description"`
+	ComposeProjectName string `json:"compose_project_name"` // `-p` arg for docker compose
+	Status             string `json:"status"`               // stopped, deploying, running, failed
+	Error              string `json:"error"`
+	CurrentRevisionID  string `json:"current_revision_id"`
+	CreatedAt          string `json:"created_at"`
+	UpdatedAt          string `json:"updated_at"`
+}
+
+// StackRevision is an append-only record of a YAML version for a stack.
+// Rollback = insert a new revision whose YAML is copied from an older one.
+type StackRevision struct {
+	ID        string `json:"id"`
+	StackID   string `json:"stack_id"`
+	Revision  int    `json:"revision"` // monotonic per stack
+	YAML      string `json:"yaml"`
+	Author    string `json:"author"`
+	DeployID  string `json:"deploy_id"`
+	Status    string `json:"status"` // pending, success, failed
+	CreatedAt string `json:"created_at"`
+}
+
+// StackDeploy records a deployment attempt of a specific revision.
+type StackDeploy struct {
+	ID         string `json:"id"`
+	StackID    string `json:"stack_id"`
+	RevisionID string `json:"revision_id"`
+	Status     string `json:"status"` // pending, deploying, success, failed, rolled_back
+	Log        string `json:"log"`
+	Error      string `json:"error"`
+	StartedAt  string `json:"started_at"`
+	FinishedAt string `json:"finished_at"`
+}
+
 // EventLog represents a persistent event log entry.
 type EventLog struct {
 	ID        int64  `json:"id"`