Standardize single profile + DISPLAY + CDP port mapping for local FSB Chrome (document)

[Trace824]

Summary

Local multi-Chrome setups confuse DISPLAY, user-data-dir, and --remote-debugging-port. Clipboard tools (xclip) and CDP clients fail when they target a different display/port than the Chrome that holds the FSB session.

Repro

• Context: Several Chrome profiles and displays on one Linux host.
• Steps:
  1. Launch Chrome A on DISPLAY :N with CDP port P.
  2. Point clipboard/CDP helpers at a different DISPLAY/port.
  3. Attempt paste or debugger attach while FSB MCP uses the extension bridge.
• Observed: paste no-ops; debugger/scripts miss the intended browser.

Code pointers (verified against /workspace/FSB)

• mcp/README.md / root README.md — bridge ports 7225/7226 (FSB hub, not Chrome CDP).
• extension/README.md — unpacked install.
• Ops practice: document a single recommended map (one profile, one DISPLAY, one CDP port) for local FSB use.

Proposed fix

Add an ops doc table: recommended one-profile layout; clarify FSB bridge ports vs Chrome --remote-debugging-port; note clipboard DISPLAY must match the Chrome window.

Acceptance / regression

• Doc exists and is linked from README.
• New contributors can run one Chrome without port/DISPLAY collisions.

Owner

ops / docs

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Priority: P2 · Owner: ops