Align the plugin-state isolation roadmap note with current green verification

The roadmap still implied that the ambient-plugin-state isolation work sat
outside a green full-workspace verification story. Current main already has
both the test-isolation helpers and the host-plugin-leakage regression, and
the required workspace fmt/clippy/test sequence is green. This updates the
remaining stale roadmap wording to match reality.

Constraint: User required fresh cargo fmt, cargo clippy --workspace --all-targets -- -D warnings, and cargo test --workspace before closeout
Rejected: Leave the stale note in place | contradicts the current verified workspace state
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: When backlog items are retired as stale, update any nearby stale verification caveats in the same pass
Tested: cargo fmt --all --check; cargo clippy --workspace --all-targets -- -D warnings; cargo test --workspace
Not-tested: No additional runtime behavior beyond already-covered regression paths

Author: Yeachan-Heo

ROADMAP.md

@@ -344,7 +344,7 @@ Priority order: P0 = blocks CI/green state, P1 = blocks integration wiring, P2 =
     - Forks inherit the parent's workspace root by default; an explicit re-bind is required to move a session to a new worktree, and that re-bind is itself recorded as a structured event so the orchestrator can audit cross-worktree handoffs.
     - Surface a `branch.workspace_mismatch` lane event so clawhip stops counting wrong-CWD writes as lane completions.
 
-    **Status.** Done. Managed-session creation/list/latest/load/fork now route through the per-worktree `SessionStore` namespace in runtime + CLI paths, session loads/resumes reject wrong-workspace access with typed `SessionControlError::WorkspaceMismatch` details, `branch.workspace_mismatch` / `workspace_mismatch` are available on the lane-event surface, and same-workspace legacy flat sessions remain readable while mismatched legacy access is blocked. Focused runtime/CLI/tools coverage for the isolation path is green, and `cargo test --workspace --exclude compat-harness` passes. `cargo clippy --workspace --all-targets -- -D warnings` still fails on pre-existing lints in unchanged `rust/crates/rusty-claude-cli/build.rs`, so that lint cleanup remains outside this roadmap item.
+    **Status.** Done. Managed-session creation/list/latest/load/fork now route through the per-worktree `SessionStore` namespace in runtime + CLI paths, session loads/resumes reject wrong-workspace access with typed `SessionControlError::WorkspaceMismatch` details, `branch.workspace_mismatch` / `workspace_mismatch` are available on the lane-event surface, and same-workspace legacy flat sessions remain readable while mismatched legacy access is blocked. Focused runtime/CLI/tools coverage for the isolation path is green, and the current full workspace gates now pass: `cargo fmt --all --check`, `cargo clippy --workspace --all-targets -- -D warnings`, and `cargo test --workspace`.
 
 ## Deployment Architecture Gap (filed from dogfood 2026-04-08)