v0.9.6: make default cr a live room workspace

[spytensor]

Linked Issue

Closes #315

Scope

This fixes the product-shape bug in the default cr path: the full-screen room is now the current user work room, not a historical transcript/dashboard shell.

Implemented:

• split read-only console snapshots from default live-room snapshots
• default live room starts with empty current-session workspace instead of .coreroom/messages.jsonl history
• center panel now renders CoreRoom Workspace, a real empty-room prompt, submitted user text, and @host / explicit @ROLE route state
• input strip is Ask @host instead of technical Composer debug output
• live-room footer removes dashboard navigation noise; read-only console keeps navigation
• real PTY dogfood now writes stale message history and fails if plain cr shows it
• v0.9.6 version, changelog, README, splash, docs, and README images updated

Not implemented:

• authenticated role-engine runtime parity inside ratatui; cr start remains the full legacy runtime path while that closes separately

Acceptance Criteria

• AC-1: Plain cr opens a live room workspace as the primary surface, not a historical Conversation transcript.
• AC-2: The default live room does not load previous .coreroom/messages.jsonl history into the center panel; read-only/debug console paths keep transcript projection.
• AC-3: Empty live room state renders a work-room prompt instead of No public request / waiting text.
• AC-4: Submitted text appears in the center workspace with @host / explicit @ROLE routing state.
• AC-5: Input strip is user-facing Ask @host, not a debug Composer panel.
• AC-6: Live-room footer removes tab/backtab dashboard navigation noise.
• AC-7: Real PTY dogfood covers plain cr, stale old history, typed input, and clean exit.
• AC-8: README/CHANGELOG/version text document v0.9.6 and corrected default shape.

Validation

Commands run:

cargo fmt --all
cargo test --all-features --locked --quiet
cargo clippy --all-targets --all-features --locked -- -D warnings
cargo build --release --locked
(cd npm && npm pack --dry-run)
python3 scripts/dogfood-v09-user-cases.py
make readme-images

Evidence:

• cargo test: pass
• cargo clippy -D warnings: pass
• release build: pass
• npm dry run: @spytensor/coreroom@0.9.6
• dogfood: DOGFOOD PASS: v0.9 local user-case gate completed
• README images regenerated: boot dashboard and control room console updated

Risk

The live room still stages routing rather than running authenticated engine turns inside ratatui. The PR makes that explicit in the workspace activity line and keeps cr start as the legacy full-turn runtime.

Rollback

Revert this PR. No migrations or persisted user state changes are introduced.