#7750 improvement(chat): unify expandable inline tool activity

Summary

• Show inline tool activity with standard body text, the shared shimmer, and matching tool icons across workspace chat, organization chat, and search.
• Limit summaries to two distinct actions plus a remaining-action count, and expand them into the full tool history for the main agent, browser, and every subagent. Use one shared disclosure, the existing scrollable viewport size, and canonical scroll-edge fades and overflow tooltips.
• Keep permission prompts, terminal handoffs, and browser takeover interactions accessible, and use canonical overflow text for suggested actions.

Type of Change

• Improvement

Testing

• 240 targeted app tests and 19 shared overflow/scroll tests passed, including streaming updates, nested agents, single countdown ownership, preserved viewport identity, accessible live names, skipped/interrupted outcomes, permissions, terminal handoffs, browser takeover, and organization surfaces.
• The compact-summary refinement passes 43 targeted tests, including duplicate-category counts and preserved terminal outcomes.
• Type-checking, lint, all 46 audits, block-registry validation, and generated-file checks passed.
• Checked production components in the local preview in both themes: keyboard expansion, full history scrolling, long-label tooltips, and 15px search shimmer.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)