docs: include GitHub Copilot CLI in root agent listings

[matthewcorven]

What does this PR do?

Brings the GitHub Copilot CLI agent to parity with the other supported coding agents in the repo's root-level documentation. Copilot is already wired up in the backend (server/pkg/agent/copilot.go, with MinVersions["copilot"] = "1.0.0"), and apps/docs/ already lists it — but several root docs (READMEs, CLI/self-hosting guides) still omitted it, so users browsing GitHub or the self-hosting flow could not tell that Copilot is supported.

This PR is documentation-only: no code, schema, or behaviour changes.

While editing the Chinese README I also added Kimi and Kiro CLI, which were missing there too (the zh README had drifted further out of date than the English one).

Related Issue

Closes #

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Refactor / code improvement (no behavior change)
• Documentation update
• Tests (adding or improving test coverage)
• CI / infrastructure

Changes Made

• README.md — added GitHub Copilot CLI to the feature blurb, daemon auto-detect list, provider picker prose, ASCII architecture diagram, and the runtime-layer table.
• README.zh-CN.md — mirrored the five English edits; additionally added Kimi and Kiro CLI which were also missing.
• CLI_AND_DAEMON.md — added a "GitHub Copilot CLI" row to the Supported Agents table (linked to https://docs.github.com/en/copilot) and added MULTICA_COPILOT_PATH / MULTICA_COPILOT_MODEL env-var rows (the model row notes that Copilot routes models through your account entitlement, so the override may not be honoured).
• CLI_INSTALL.md — added copilot to the inline agent-detection list strings (4 occurrences).
• SELF_HOSTING.md — added a [GitHub Copilot CLI](https://docs.github.com/en/copilot) (copilot on PATH) bullet between Codex and OpenClaw in the supported-agents list.
• SELF_HOSTING_ADVANCED.md — added MULTICA_COPILOT_PATH and MULTICA_COPILOT_MODEL rows to the agent-specific overrides table.

How to Test

1. On the PR's Files changed tab, confirm only the six root .md files above are touched.
2. Run a quick parity grep locally:

   grep -nE "Copilot|copilot" README.md README.zh-CN.md CLI_AND_DAEMON.md CLI_INSTALL.md SELF_HOSTING.md SELF_HOSTING_ADVANCED.md

   Expect matches in each of the spots described under Changes Made.
3. Visually skim the rendered files on GitHub and confirm Copilot appears alongside the other agents in: feature list, agent-detect list, provider picker prose, architecture diagram, runtime-layer table, supported-agents table, env-var override table.
4. Cross-check against apps/docs/content/docs/ (already at parity) so the marketing/docs site and the root docs now agree.

Checklist

• I have included a thinking path that traces from project context to this change
• I have run tests locally and they pass
• I have added or updated tests where applicable
• If this change affects the UI, I have included before/after screenshots
• I have updated relevant documentation to reflect my changes
• I have considered and documented any risks above
• I will address all reviewer comments before requesting merge

AI Disclosure

AI tool used: GitHub Copilot in VS Code (Claude Opus 4.7)

Prompt / approach:
Asked the assistant to survey the fork and identify any lack of parity for GitHub Copilot CLI versus the other supported agents, then prepare a PR. Workflow:

1. Surveyed the repo and confirmed Copilot is already implemented in server/pkg/agent/copilot.go with a registered MinVersions entry.
2. Audited every root-level documentation surface (README.md, README.zh-CN.md, CLI_AND_DAEMON.md, CLI_INSTALL.md, SELF_HOSTING.md, SELF_HOSTING_ADVANCED.md) for Copilot mentions and compared against the listings of other agents.
3. Confirmed apps/docs/content/docs/ was already at parity, so it was deliberately left untouched.
4. Applied minimal, additive edits — placing Copilot consistently where Codex / Claude Code / Cursor already appeared, and matching surrounding formatting.
5. While mirroring the changes into the Chinese README, noticed Kimi and Kiro CLI were also missing and added them too.

Follow-up not in this PR: Chinese MDX mirrors under apps/docs/content/docs/*.zh.mdx were not audited; happy to do that as a separate PR if maintainers want.

Screenshots (optional)

N/A — documentation only.

[vercel]

@matthewcorven is attempting to deploy a commit to the IndexLabs Team on Vercel.

A member of the Team first needs to authorize it.