feat(conversation): add task completion walkthrough card and parser

[EduCosta85]

Pull Request

Description

This PR introduces a structured Task Completion Walkthrough feature for AionUi. When an assistant or agent completes a complex task or execution, it can deliver a structured walkthrough summarizing what was accomplished.

Key capabilities added:

1. Semantic Parser (walkthroughParser.ts):
   • Detects and parses [WALKTHROUGH]...[/WALKTHROUGH] blocks (including streaming with unclosed tags) and standard # Walkthrough markdown sections.
   • Automatically classifies sections into standard categories (delivered, howItWorks, usage, notes, and custom) using multilingual keywords.
2. Interactive UI Component (WalkthroughCard):
   • Polished card built with Arco Design (@arco-design/web-react) and IconPark (@icon-park/react).
   • Supports global collapse/expand as well as per-section toggling.
   • Quick one-click "Copy Walkthrough" button to copy clean markdown to clipboard.
   • Renders rich markdown (tables, code blocks, syntax highlighting, local file links) in each section.
3. Chat Integration (MessageText.tsx & turnCopy.ts):
   • Strips raw [WALKTHROUGH] tags from ordinary message bubbles and displays the dedicated WalkthroughCard.
   • Avoids empty bubble containers when the message is solely a walkthrough.
   • Preserves clean markdown content when copying entire turns.
4. i18n & Agent Skill:
   • Fully localized across all 13 supported languages.
   • Added .claude/skills/walkthrough/SKILL.md and indexed in AGENTS.md.
5. Comprehensive Tests:
   • 24 unit & DOM tests covering parser, UI card, and MessageText integration.

Related Issues

• Closes #

Type of Change

• feat — New feature (non-breaking change which adds functionality)

Atomic PR Checklist (Rule 1)

• This PR contains exactly one feature or bug fix that cannot be further decomposed
• The PR title follows Conventional Commit format: <type>(<scope>): <subject> (English)

Local Checks (Rule 3)

• bun run format — formatting passes
• bun run lint — no lint errors (skip if no .ts/.tsx changed)
• bunx tsc --noEmit — no type errors (skip if no .ts/.tsx changed)
• bunx vitest run — tests pass (5,005 tests passing)
• i18n validated (bun run i18n:types + node scripts/check-i18n.js) — only if src/renderer/, locales/, or src/common/config/i18n/ changed; N/A otherwise
• New/changed user-facing text uses i18n keys (no hardcoded strings)

Runtime Verification

• Verified on macOS
• Verified on Windows
• Verified on Linux
• I have performed a self-review of my own code

[codecov]

Codecov Report

❌ Patch coverage is 85.81560% with 20 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...es/components/WalkthroughCard/walkthroughParser.ts	83.11%	0 Missing and 13 partials ⚠️
...s/conversation/Messages/components/MessageText.tsx	76.47%	0 Missing and 4 partials ⚠️
...tion/Messages/components/WalkthroughCard/index.tsx	93.33%	2 Missing and 1 partial ⚠️

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