feat(cli): add transcript navigation and presentation controls

[limityan]

Summary

• Add OpenCode-compatible transcript navigation through /timeline, with newest-first user-message points, move-to-preview, and an Enter-confirmed scroll anchor that remains stable while an active turn grows.
• Add OpenCode-compatible presentation controls: /timestamps with /toggle-timestamps, /thinking with /toggle-thinking, and palette-only Tool details. No new shortcuts or invented slash aliases are introduced.
• Keep Embedded and Shared TUI behavior aligned while persisting client-local presentation defaults safely across concurrent TUI processes.

Design

• Reuse ChatState transcript facts; timeline is a read-only CLI projection and adds no Runtime operation, IPC message, or Relay behavior.
• Extract one conversation-point selector shared by timeline and the existing fork dialog, and reuse the per-message render/layout cache for drawing, line counting, preview, and committed jumps.
• Use one disclosure override model for thinking and tool cards: a global configured default plus a per-block inversion.
• Persist focused config mutations by locking, reloading the latest TOML, merging one setting, and atomically replacing the file. Theme selection uses the same path so a stale Shared TUI snapshot does not overwrite presentation preferences.

OpenCode entry compatibility

Capability	Entry
Timeline	/timeline
Timestamps	/timestamps, /toggle-timestamps
Thinking	/thinking, /toggle-thinking
Tool details	Command palette only

Scope

• CLI/TUI and existing CLI documentation only.
• No Agent Runtime, IPC, Relay, workflow, or superpowers/ changes.
• Timeline remains read-only; fork, undo, copy, and message mutation retain their existing owners and commands.

Verification

• rustfmt --edition 2021 --check on all changed Rust files
• git diff --check gcwing/main...HEAD
• cargo check -p bitfun-cli --locked
• cargo test -p bitfun-cli --locked -- --skip dispatch::workspace::tests::reported_sync_failure_allows_a_new_operation_to_take_over --skip dispatch::workspace::tests::legacy_sync_failure_without_operation_id_is_reported_then_retryable --skip dispatch::workspace::tests::reprovisioning_a_missing_checkout_never_resets_the_job_branch
  • 594 CLI unit tests passed after the CLI-overlapping rebase
  • ACP, compatibility entrypoint, exec, plugin, product-assembly, and terminal/PTY integration suites all passed
• After the final unrelated Web-only main update: cargo test -p bitfun-cli --locked opencode_navigation_and_presentation_actions_keep_exact_entrypoints

The three skipped tests are existing Windows Dispatch platform/extended-path failures and are outside this PR's call paths.