refactor(workload): plugin architecture wave + apps UI + volume scopes

Completes the workload-first refactor's plugin layer:

- internal/workload/plugin/ — Source/Trigger plugin contract,
  registry, types (Workload, DeploymentIntent, InboundEvent,
  PublicFace). Self-registering init() pattern + blank-import
  in cmd/server/main.go.
- Source plugins: image (blue-green with multi-face proxy routing),
  compose, static. Trigger plugins: registry, git, manual.
- internal/deployer/dispatch.go — DispatchPlugin/Teardown/Reconcile
  seam routing the legacy deployer through plugins.
- internal/api/workload_*.go — REST surface: workloads, env,
  volumes, chain (parent/children), promote-from. hooks.go
  serves /api/hooks/kinds/{kind}/schema for the wizard.
- internal/store: workload_env (encrypt-at-rest secrets) and
  workload_volumes tables, keyed on workload_id.
- cmd/server/static_backend.go — phantom-row adapter delegating
  the static source plugin to the legacy staticsite.Manager
  (deleted at hard cutover once the static inline port lands).
- web/src/routes/apps/ — /apps list + /apps/new wizard +
  /apps/[id] detail with kind-aware compose / image / static
  forms (Advanced JSON toggle), env panel, volumes panel,
  webhook panel, chain panel, manual deploy.

Volume scope generalization (v2 resolver):

- internal/volume.ResolveWorkloadPath (workload-keyed, sits
  next to legacy ResolvePath). Honors all VolumeScope values:
  absolute, ephemeral, instance, stage, project, project_named,
  named. internal/workload/plugin/source/image/image.go
  computeMounts wires settings + imageTag through. Coverage in
  internal/volume/resolver_test.go (portable Linux/Windows via
  t.TempDir).

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

internal/workload/plugin/registry.go

@@ -0,0 +1,27 @@
+package plugin
+
+// AllSources returns a snapshot of every registered Source keyed by kind.
+// Snapshot semantics: the caller may iterate freely without holding any
+// lock. Mutating the returned map does not affect the registry.
+func AllSources() map[string]Source {
+	sourcesMu.RLock()
+	defer sourcesMu.RUnlock()
+	out := make(map[string]Source, len(sources))
+	for k, v := range sources {
+		out[k] = v
+	}
+	return out
+}
+
+// AllTriggers returns a snapshot of every registered Trigger keyed by kind.
+// Used by the single webhook ingress to fan an InboundEvent out across all
+// triggers without per-call locking.
+func AllTriggers() map[string]Trigger {
+	triggersMu.RLock()
+	defer triggersMu.RUnlock()
+	out := make(map[string]Trigger, len(triggers))
+	for k, v := range triggers {
+		out[k] = v
+	}
+	return out
+}