feat(web): clearer icons for the workspace panel controls

[maria-rcks]

replaces the filter glyph on thread details with square-menu. the terminal drawer keeps its original panel-bottom; PanelRight and Maximize2 / Minimize2 stay unchanged.

original candidate galleries below use the actual control components. each candidate appears at 16px in the app's ghost toggle, unpressed then pressed.

runner-ups:

• Info: readable, but suggests passive information; thread details also contains workspace and git actions.
• LayoutList: conveys organized content, but the small boxes add visual noise at 16px.
• PanelRightOpen: suggests a one-way opening action and resembles the adjacent right-panel toggle.
• Terminal / SquareTerminal: considered for the terminal drawer; the original PanelBottom is retained.

verification: web typecheck and scoped lint passed on blacksmith for 63d995b018. captured the actual unpressed control row in dark and light. details and right-panel toggles open and close. the terminal drawer opens and closes with the correct pressed state; terminal session content remains unavailable in the copied dev state. no matching action icons needed changes in the command palette, keybinding help, mobile, or user docs. desktop shares this component; native desktop was not separately exercised. provider adapters and contracts are unchanged.

Written by gpt-6-astra (Codex) in T3 Code

[macroscopeapp]

Approvability

Verdict: Approved at 63d995b

Macroscope's review found this PR approvable — This single-file change only replaces an existing panel-control icon while preserving the toggle’s state, interactions, labels, and panel behavior. It introduces no schema, configuration, deployment, or sensitive-data changes.

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Dismissing prior approval to re-evaluate 63d995b