refactor: workspace secrets-core + secrets-mcp MCP SaaS

- Split library (db/crypto/service) and MCP/Web/OAuth binary
- Add deploy examples and CI/docs updates

Made-with: Cursor

crates/secrets-mcp/Cargo.toml

@@ -0,0 +1,44 @@
+[package]
+name = "secrets-mcp"
+version = "0.1.0"
+edition.workspace = true
+
+[[bin]]
+name = "secrets-mcp"
+path = "src/main.rs"
+
+[dependencies]
+secrets-core = { path = "../secrets-core" }
+
+# MCP
+rmcp = { version = "1", features = ["server", "macros", "transport-streamable-http-server", "schemars"] }
+
+# Web framework
+axum = "0.8"
+axum-extra = { version = "0.10", features = ["typed-header"] }
+tower = "0.5"
+tower-http = { version = "0.6", features = ["cors"] }
+tower-sessions = "0.14"
+
+# OAuth (manual token exchange via reqwest)
+reqwest.workspace = true
+
+# Templating - render templates manually to avoid integration crate issues
+askama = "0.13"
+
+# Common
+anyhow.workspace = true
+chrono.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+sha2.workspace = true
+rand.workspace = true
+sqlx.workspace = true
+tokio.workspace = true
+tracing.workspace = true
+tracing-subscriber.workspace = true
+uuid.workspace = true
+dotenvy.workspace = true
+urlencoding = "2"
+schemars = "1"
+http = "1"