feat: encrypted secrets vault across CLI, desktop, dashboard, and backend

Local vault (apps/cli): clean-room PRMVLT01 format — Argon2id →
XChaCha20-Poly1305, AEAD-bound header, atomic writes. vault:* / secrets:*
/ inject (primora:// refs) / agent credential broker (dummy tokens in the
child, real secret on the wire) / TTL sessions / stack:* operator group.

Project vault (backend): core.project_secrets, AES-256-GCM via the
platform encryptor. Metadata-only list, audit-logged reveal, and
secret://NAME refs resolved at job delivery — refs stored, values never.

Surfaces: dashboard Vault page (+ local-vault card under the Tauri
shell), desktop vault window via IPC to the primora binary,
secrets:* --remote CLI mode, metadata/write-only MCP tools so agents
consume secrets via secret:// refs without holding plaintext.

Authored By: TDvorak <[email protected]>

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/internal/handlers/http.go

@@ -116,6 +116,10 @@ func (h *HTTPHandler) Register(router *gin.Engine) {
 	api.DELETE("/projects/:projectID/jobs/:jobID", h.deleteJob)
 	api.GET("/projects/:projectID/jobs/:jobID/runs", h.listJobRuns)
 	api.POST("/projects/:projectID/jobs/:jobID/run", h.runJob)
+	api.GET("/projects/:projectID/secrets", h.listProjectSecrets)
+	api.PUT("/projects/:projectID/secrets/:name", h.setProjectSecret)
+	api.DELETE("/projects/:projectID/secrets/:name", h.deleteProjectSecret)
+	api.POST("/projects/:projectID/secrets/:name/reveal", h.revealProjectSecret)
 	api.GET("/projects/:projectID/realtime/stream", h.realtimeStream)
 	api.GET("/buckets/:bucketID/objects", h.listObjects)
 	api.POST("/buckets/:bucketID/objects", h.uploadObject)