feat(templates): v2 — multi-service graph templates, expressions, compose import

Config v2 adds services[] to TemplateConfig: members declare key, type
(web|worker|cron|database), runtime, environment, volumes and depends_on.
Deploy topo-sorts the graph, creates databases first (managed DBs attached
to the project network under their key as DNS alias), then services with
resolved env, and enqueues a real deployment per service.

Expressions: {{secret}}, {{secret(N)}}, {{random:N}}, {{VAR}},
{{VAR:-default}} and {{service.<key>.<prop>}} with props host, port, url,
user, password, database. Credential-bearing refs (password/url) mark the
consuming variable secret — stored encrypted, masked in plan output.
Single-service template secret vars are now encrypted at rest too.

New endpoints: POST /templates/:id/plan (dry-resolve with missing/
unresolved reporting), POST /templates/import/compose (compose YAML →
v2 config; known db images become managed databases, build: flagged in
warnings), POST /templates/deploy (ad-hoc graph deploy — the compose
import companion).

Surfaces: CLI gains templates plan/import-compose/deploy-graph plus
--name/--var on deploy; 3 new MCP tools (88 total); OpenAPI + generated
frontend types; TemplatesPage shows stack members, deploys graphs without
a name field, renders the created resource list, and ships an
Import Compose modal feeding the template editor.

Seeded: WordPress + MySQL and n8n + PostgreSQL graph templates.

Partial-failure cleanup: resources created by a failed graph deploy are
removed (rows, containers, volumes).

Verified live: wordpress-stack deploy created a managed MySQL attached to
the project network as `db`; an inline pg+redis+nginx graph deployed with
DATABASE_URL=postgresql://app:<gen>@pg:5432/shop resolvable in-container.

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

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

app/backend/go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/gorilla/websocket v1.5.3
 	github.com/lib/pq v1.10.9
 	github.com/miekg/dns v1.1.72
+	github.com/minio/minio-go/v7 v7.0.95
 	github.com/modelcontextprotocol/go-sdk v1.7.0
 	github.com/pressly/goose/v3 v3.24.1
 	github.com/robfig/cron/v3 v3.0.1
@@ -23,6 +24,7 @@ require (
 	github.com/stretchr/testify v1.11.1
 	golang.org/x/crypto v0.57.0
 	golang.org/x/term v0.46.0
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
@@ -59,7 +61,6 @@ require (
 	github.com/mfridman/interpolate v0.0.2 // indirect
 	github.com/minio/crc64nvme v1.0.2 // indirect
 	github.com/minio/md5-simd v1.1.2 // indirect
-	github.com/minio/minio-go/v7 v7.0.95 // indirect
 	github.com/moby/docker-image-spec v1.3.1 // indirect
 	github.com/moby/sys/atomicwriter v0.1.0 // indirect
 	github.com/moby/term v0.5.2 // indirect
@@ -106,7 +107,6 @@ require (
 	golang.org/x/time v0.15.0 // indirect
 	golang.org/x/tools v0.49.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 	gotest.tools/v3 v3.5.2 // indirect
 	modernc.org/sqlite v1.39.0 // indirect
 )