feat(cli): add TUI session controls and context compaction

[limityan]

Summary

• Align interactive TUI session entry points with OpenCode: add /status, /clear (/new), and session browser aliases /sessions, /resume, /continue, and /history.
• Add OpenCode-compatible manual context compaction through /compact with /summarize as its only alias. Both Embedded and Shared TUI use the same runtime-owned operation; no new shortcut or BitFun-specific command is introduced.
• Show a truthful latest-primary-model context snapshot in TUI status instead of presenting it as a whole-session total.

Design and behavior

• Add one narrow AgentSessionCompactionPort and keep compression policy, prompts, context replacement, persistence, and terminal ownership in Core.
• Extend the private first-party Shared TUI IPC to protocol v8 with an idle/current-controller CompactSession operation and caller-owned turn identity for disconnect cancellation and unknown outcomes.
• Admit dialog and maintenance turns atomically. Manual compaction reads context only after it owns the Session, remains cancellable during planning, and ignores late cancellation once atomic commit begins.
• Persist manual compaction as a transcript-visible but model-invisible maintenance Turn. Live and restored views retain the same compression ID, tool payload, applied fact, and terminal error semantics.
• Preserve normal user retry from SessionState::Error while keeping maintenance operations idle-only.

Scope

• No Relay, Server, Peer, ACP, SDK Host, extension, customization, compression-algorithm, or public protocol changes.
• The IPC version change is limited to the unpublished local first-party TUI protocol; same-version client and runtime are required as before.

Adversarial review

An independent combined-diff review found and closed issues in atomic turn admission, post-commit terminal finalization, persisted transcript restoration, compression identity/payload parity, error-state retry, and cancelled/error transcript parity. The final review found no remaining P1/P2 blockers.

Validation

• cargo test -p bitfun-runtime-ports
• cargo test -p bitfun-agent-runtime
• cargo test -p bitfun-agent-runtime-ipc (45 passed)
• cargo test -p bitfun-cli (493 unit tests plus integration suites passed)
• cargo test -p bitfun-core manual_compaction --features product-full -- --nocapture (6 passed)
• cargo test -p bitfun-core maintenance --features product-full -- --nocapture (5 passed)
• cargo test -p bitfun-events (20 passed)
• cargo check -p bitfun-core --features product-full
• node scripts/check-core-boundaries.mjs
• changed-file rustfmt --check
• git diff --check

cargo check --workspace was also attempted. Rust compilation reached the Desktop build script, which stopped because the generated, untracked src/mobile-web/dist directory is absent in this clean worktree. No unrelated generated frontend output is included in this PR.