feat(tui v2): plan card + done annotation + /cost + /review wiring

[shenhao-stu]

• Plan card (📋): per-session message-scan with plan_scan_baseline so /continue of a finished session doesn't auto-resurrect old plan cards; prefers <summary>当前步骤: over the long plan-item echo; placeholder while enter_plan_mode is armed but plan.md hasn't been written yet.
• Done annotation (⠿ {Verb} for Xm Ys · ↑ N · ↓ M): post-turn elapsed
  • per-call token deltas, frozen at done so the line stays put across re-mounts. Spinner annotation gated on cumulative deltas past stream-start baselines — fixes ↓ 16 showing immediately on prompt submit.
• fold_turns regex anchored to line-start (^ + MULTILINE) so embedded backticks in tool output (e.g. N|\```` gutter from file_read) don't pair with later real fences. ~100x faster on long /continue sessions.
• /cost: per-session card + /cost all; Context window line now reads GA's actual char cap via cost_tracker.context_window_chars(backend) = backend.context_win * 3 (the trim_messages_history trigger threshold in llmcore.py), so the percentage reflects real budget and respects mykey.py overrides. Unit changes from token to character. Dropped the model-theoretical _CTX_LIMITS table (never actually constrained anything). Subagent log scan via cost_tracker.scan_subagent_logs aggregates temp/*/stdout.log since TUI start.
• /review: standalone in-session reviewer; reuses review_cmd.handle to render the inline prompt and submits as a normal user task.
• llmcore: emit [Output] tokens=N for chat_completions / responses modes (already emitted for messages SSE) so cost_tracker scopes output tokens uniformly across all three API modes.
• review_inline_prompt.{txt,en.txt}: filled out the in-session review discipline — Three Iron Rules, Q1-Q4 framing, severity examples, 8 false-positive rules expanded, 8 wording rules expanded, 8-item self-check. ZH/EN both grow ~80 lines.
• memory/review_sop.md: rewrite 52 → 191 lines, 11 sections covering quick-start, entry files, Three Iron Rules, 5-step workflow, severity, output protocol, relationship to plan_sop / verify_sop. Style mirrors plan_sop.md + autonomous_operation_sop.md.

Files: frontends/{tuiapp_v2,tuiapp,cost_tracker,plan_state}.py, llmcore.py, memory/review_sop.md, memory/review_sop/review_inline_prompt.{txt,en.txt}, .gitignore (allowlist new SOP).