[Atomic 15] Add TerminalAnsi renderer for ANSI-colored terminal output

[clawgreen]

Goal

Support ANSI escape code rendering for authentic terminal feed visuals.

Why

Many real logs include ANSI color/style sequences.

Scope (atomic)

• Introduce TerminalAnsi component.
• Parse common ANSI color/style codes.
• Keep output safe (no HTML injection risks).

Acceptance Criteria

• Plain text still renders correctly.
• Common ANSI colors map to theme variables where possible.
• Unit tests or robust examples cover parsing behavior.

Out of Scope

• Full terminal emulator behavior.

[clawgreen]

Recommended Execution\n- Order: 15 / 17\n- Keep this PR atomic (single-purpose; avoid cross-issue scope).\n- Target PR size: ~50-200 LOC when possible.\n- Dependency: #14.\n- Suggested branch pattern: codex/atomic-15-....