Description

This PR improves the workbench and agent chat experience:

• Refines sidebar alignment, spacing, typography, hover states, and pinned conversation styling.
• Preserves grouped agents and nested conversations on the discovery page, while showing the selected agent’s conversations inside agent chat.
• Adds responsive floating controls without introducing a header. As available width decreases, the title and secondary controls hide progressively, keeping the expand button accessible.
• Adds overflow-only tooltips for truncated titles.
• Preserves sidebar state during conversation switching and new conversation creation, while resetting it when navigating between pages.
• Fixes repeated entry into the same agent conversation.
• Balances chat margins and prevents floating controls from blocking navigation hover menus or conversation content.
• Improves Chinese and English localization across resource pickers, configuration dialogs, validation messages, and accessibility labels.
• Integrates the latest develop changes, preserving conversation activity synchronization, routing, shared resource pickers, and loading boundaries.

Review Follow-up

• Initializes i18n with the maintained locale catalogs in affected resource component tests.
• Updates inline message editing tests to wait for asynchronous runtime initialization.
• Converts CHAT-SIDEBAR-D4-002 from manual acceptance into an executable Playwright regression case.
• Resolves duplicate business rule IDs introduced by merging develop.

Validation

After merging develop:

• Passed 444 workbench tests.
• Passed 49 targeted component tests covering sidebar state, floating controls, layout persistence, authorization recovery, and activity synchronization wiring.
• Passed CHAT-SIDEBAR-D4-002 browser regression, covering:
  • Workbench and agent chat collapse/expand behavior.
  • Draft preservation and new conversation behavior.
  • Route navigation and sidebar state restoration.
  • Mobile sidebar drawer interactions.
  • Progressive control visibility across multiple viewport widths.
  • Expand button positioning, symmetric gutters, and navigation hover layering.
• Passed TypeScript type checking.
• Passed formal test asset validation.
• Passed formatting and copyright checks for the conflict-resolution files.
• Confirmed no remaining local merge conflicts.