[docs] Mark delivered Copilot usage, sessions, and dashboard support in the matrix

[ousamabenyounes]

Problem

The support matrix still marks GitHub Copilot CLI as unsupported for its last three capabilities:

• usage
• sessions
• dashboard

That row is stale. Issue #612 was specifically scoped to those three capabilities, and merged PR #666 added privacy-safe Copilot telemetry, session lifecycle correlation, usage/token collection with a missing-token fallback, and dashboard records. Its validation included an authenticated Copilot CLI create/resume probe and the relevant RED-to-GREEN test coverage.

The stale matrix makes the completed Copilot delivery look unfinished and contradicts the merged implementation and documentation.

Scope

• Verify the current main behavior and tests still support all three claims delivered by feat: add privacy-safe Copilot telemetry #666.
• Change the GitHub Copilot CLI row from — to ✓ for usage, sessions, and dashboard in all five support matrices:
  • README.md
  • README.zh-CN.md
  • README.ja.md
  • README.ko.md
  • README.th.md
• Keep the translated tables structurally identical.
• If verification finds a real behavioral regression, do not mark that capability supported: report it and split the executable defect into its own focused issue/PR.

Acceptance criteria

• The three claims are backed by current tests or a focused real-CLI verification, not only by the historical PR description.
• All five README matrices show the same Copilot capability values.
• No unrelated capability rows or runtime behavior change.
• Documentation checks and relevant existing telemetry/session/dashboard tests pass.

Evidence

• [feat] Add Copilot usage, sessions, and dashboard telemetry #612 — approved scope for Copilot usage, sessions, and dashboard telemetry.
• feat: add privacy-safe Copilot telemetry #666 — merged implementation and authenticated Copilot CLI validation.
• fix(local-agent): report user-scope resources from the right base dir #716 — later fix for user-scope resource reporting; it does not implement these three telemetry columns.
• fix(hooks): list each tool's own built-in hook set #718 — later fix for per-tool hook listing; it does not implement these three telemetry columns.