Model live room conversation task cards

[spytensor]

Linked Issue

Closes #304

Scope

Adds a live room conversation view model for the unified full-screen room. The model keeps the center conversation focused on user/host output and direct user-addressed specialist turns, while host-managed internal delegation is represented as task cards outside the public transcript.

Implemented:

• LiveRoomConversationPanel for public turns, internal task cards, hidden internal count, side-rail count, and display-only authority boundary.
• LiveRoomTurnKind for user, host, and direct specialist public turns.
• InternalTaskCard for compact host-managed delegation rows.
• TUI conversation pane now renders from the live room model instead of directly reading snapshot internals.
• Tests proving public/internal visibility and task card projection from the existing snapshot fixture.

Acceptance Criteria

• AC-1: Define a live room conversation view model for user turns, host turns, direct specialist turns, and host-managed internal task cards.
• AC-2: Preserve existing conversation visibility rules: user/host stays public, user-addressed specialist replies can be public, host-managed internal delegation stays out of public chat.
• AC-3: Add fixtures showing public conversation plus internal delegation cards.
• AC-4: Do not infer completion/evidence from rendered prose.
• AC-5: Keep cr console --snapshot compatible with existing CoreRoomSnapshot conversation projection.

Changed Files

• src/console_conversation.rs — live room conversation model and task-card projection.
• src/console_tui.rs — conversation pane renders from the live model.
• tests/console_conversation_test.rs — fixtures for public/direct/internal task-card behavior and display-only authority.

Validation

• cargo fmt --all -- --check — pass
• cargo test --test console_conversation_test --locked --quiet — pass, 4 tests
• cargo test --test console_tui_test --locked --quiet — pass, 7 tests
• cargo clippy --all-targets --all-features --locked -- -D warnings — pass
• cargo test --all-features --locked --quiet — pass
• git diff --check — pass

Evidence / Completion Boundary

The new model explicitly carries ConversationAuthority::DisplayOnly. It does not expose completion, approval, release readiness, CI, or evidence-closure state. Those remain sourced from WorkOrders, gates, Evidence Packets, CI, tracker rows, and source facts.

Risk

Low. This changes the console conversation projection and keeps existing snapshot shape compatible. It does not change the default cr entrypoint or live role runtime.

Rollback

Revert this PR. No migrations, persisted state, release metadata, or user data are changed.

Tracker Update

• Tracker issue: v0.9.4: unify full-screen dashboard with live conversation composer #301
• Updated checkbox: v0.9.4: model live room conversation and internal task cards #304 checked
• Updated M-AC: M-AC-3 checked
• Evidence Ledger row: v0.9.4: model live room conversation and internal task cards #304 -> PR Model live room conversation task cards #309, in review, conversation/task-card tests/full test/clippy evidence