Add non-default live room bridge

[spytensor]

Linked Issue

Closes #305

Scope

Adds the first non-default unified room bridge behind cr console --live-room. This does not replace the default cr path and does not change cr console --snapshot; it creates a staged live room path where the composer and dashboard render together and submissions are routed through existing REPL parse semantics.

Implemented:

• console_room bridge that routes composer submissions through repl::parse_line.
• bare text dispatches to the configured host role.
• explicit @role dispatches to the target role.
• @all broadcast is recognized.
• supported slash commands produce clear live-room bridge actions.
• unsupported runtime-only slash commands produce clear guidance to use cr start until dogfood parity closes.
• permission/action overlays can be surfaced without mutating snapshot conversation facts.
• cr console --live-room non-default TTY path with composer/dashboard rendering together.
• text-render test proving dashboard, conversation, task cards, composer, and bridge status render in one frame.

Acceptance Criteria

• AC-1: Add an integrated full-screen room loop behind a non-default command/flag.
• AC-2: Dispatch bare text to the configured host role and explicit @role text to the target role using existing routing semantics.
• AC-3: Preserve slash commands required for normal operation or explicitly block unsupported commands with clear messaging.
• AC-4: Surface permission prompts in the room without corrupting the dashboard or composer.
• AC-5: Update dashboard panels from structured state, not UI-owned guesses.
• AC-6: Keep cr console --snapshot read-only/debug mode unchanged.

Preserved / Deferred REPL Behavior Matrix

Behavior	#305 status	Evidence
bare user text -> host	preserved in bridge	live_room_routes_bare_text_to_host_and_preserves_public_user_turn
explicit @role -> target	preserved in bridge	live_room_routes_explicit_role_mentions_with_existing_repl_semantics
@all broadcast parse	recognized by bridge	LiveRoomAction::Broadcast
/help, /exit, /halt, /fresh, /refresh, /permissions, /allow, /deny, /host	supported/staged with explicit bridge status	live_room_command_specs, bridge route arms
/journal, /patch, /compact, /resume, /transcript, /stop, /welcome	explicitly blocked in live-room preview	live_room_blocks_runtime_only_slash_commands_with_clear_message
permission/action prompt overlay	supported without snapshot mutation	permission_overlay_stays_out_of_snapshot_conversation
actual engine role execution and permission bridge socket	deferred to #306 dogfood/parity	out of scope for #305
default cr entrypoint replacement	deferred	out of scope for #305

Changed Files

• src/console_room.rs — non-default live room bridge and routing model.
• src/console_tui.rs — cr console --live-room TTY loop and composer/dashboard rendering.
• src/main.rs — adds non-default --live-room flag; keeps --snapshot read-only.
• src/lib.rs — exports console_room.
• tests/console_room_test.rs — integration-style bridge and render tests.

Validation

• cargo fmt --all -- --check — pass
• cargo test --test console_room_test --locked --quiet — pass, 5 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
• cargo run --locked --quiet -- console --help — pass; help shows --live-room and keeps --snapshot
• git diff --check — pass

Risk

Medium. This introduces a new non-default TTY input loop, but it is isolated behind cr console --live-room, keeps cr console --snapshot unchanged, and does not alter the default cr startup behavior.

Rollback

Revert this PR. No migrations, persisted project 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: integrate live room bridge behind non-default entrypoint #305 checked
• Updated M-AC: M-AC-4 and M-AC-5 checked
• Evidence Ledger row: v0.9.4: integrate live room bridge behind non-default entrypoint #305 -> PR Add non-default live room bridge #310, in review, bridge/render tests/full test/clippy evidence