Draft Milestone 4 scope and mark progress in docs

docs/OrbitHub_v0_Spec_CPP_QtWidgets.md

@@ -77,3 +77,17 @@ OrbitHub uses a two-window model:
 - Per-session timestamped event log and user-friendly error mapping
 - Profile schema extended with `private_key_path` and `known_hosts_policy`
 - Tag: v0-m3-done
+
+---
+
+## Milestone 4 (Draft)
+
+- Make SSH sessions actually usable as interactive sessions inside OrbitHub
+- Replace placeholder surface with interactive SSH terminal panel (stream output + send input)
+- Add SSH host-key trust prompt flow for `Ask` policy
+- Improve auth flow UX for password / private key at connect time
+- Preserve responsive UI under active session output
+- Add terminal/session utilities (`Clear Terminal`, improved output visibility)
+- Keep session controls stable (`Connect`, `Disconnect`, `Reconnect`, `Copy Error`)
+- Add validation and diagnostics coverage for host-key, auth, and reconnect behavior
+- Planned Tag: v0-m4-done (after completion approval)

docs/PROGRESS.md

@@ -60,3 +60,18 @@ Delivered:
 
 Git:
 - Tag: `v0-m3-done`
+
+## Milestone 4 - Interactive SSH Session UX
+
+Status: In Progress
+
+Started:
+- Milestone 4 draft added to spec
+- Interactive SSH terminal panel wiring started (backend output stream + input send path)
+- Host-key confirmation request/response signal flow added (`Ask` policy path)
+- `known_hosts_policy` defaults and profile dialog options updated to include `Ask`
+
+Pending:
+- End-to-end interactive behavior hardening across Linux/macOS/Windows
+- Terminal UX polish (control keys, resize behavior, output formatting)
+- Additional diagnostics and integration test coverage for reconnect/auth/host-key scenarios