feat: implement core Roku ECP adapter

Add SSDP discovery plus the main ECP app, state, and key control flows so
Milestone 2 has a working Roku foundation with parser and key-mapping tests.

PROJECT_MAP.md

@@ -19,7 +19,7 @@ script and control smart TVs through a stable, brand-agnostic API.
 
 ## Project Status
 
-**Phase:** Milestone 1 scaffolded. Foundation compiles; runtime logic not started.
+**Phase:** Milestone 2 in progress. Core Roku ECP support exists; daemon and CLI wiring are still pending.
 **Platform v1:** Roku only (via ECP HTTP API)
 **Language:** Rust
 **Crate type:** Binary (single binary distribution target)
@@ -56,7 +56,7 @@ tvctl/
 │   │   └── mod.rs
 │   └── adapters/           ← Platform adapters and shared types
 │       ├── mod.rs          ← Adapter trait definition and core data shapes
-│       └── roku/           ← Roku ECP adapter scaffold
+│       └── roku/           ← Roku ECP adapter implementation
 │           └── mod.rs
 └── cache/                  ← Runtime cache (gitignored)
 ```
@@ -332,11 +332,10 @@ enabled = true
 
 ## What Has NOT Been Started
 
-- Roku ECP transport and device discovery logic
 - Daemon runtime, socket transport, and persistence logic
 - HTTP route handlers and request validation
 - Real CLI command handling beyond skeleton parsing
-- Any tests
+- Integration and hardware validation coverage
 - CI/CD configuration
 - Release/packaging