Rework the install documentation

[alistair3149]

Reworks the install documentation. The section carried the server's launch configuration nine times over (five JSON blocks, an inline code --add-mcp payload, two VS Code badge payloads, one Cursor base64), and they had already drifted apart. It is now stated once.

167 lines to 100, nine copies to one, while adding a client and retiring a dead channel.

Commits

-y on every npx path	Aligns the README with the plugin manifests, which already passed it. Also re-encodes the three one-click badges: the Cursor payload was malformed (whole command line in the command field, no args), and the VS Code badges used a superseded dialect where both editions opened the same build.
Retire the Gemini CLI channel	Gemini CLI stopped serving consumer Google AI tiers on 18 June 2026. Deletes gemini-extension.json and unwires it from the release sync, where it was being synced on every release.
State the configuration once	One canonical block plus a `Client
Document OpenCode	The one client whose configuration shape genuinely differs (mcp key, command array, environment rather than env).
Record the invariant	AGENTS.md gains an "Adding a client" rule, so the duplication does not grow back.
Two correction commits	Fixes found in review; see below.

A correction worth stating plainly

The -y work was originally justified as fixing a first-run hang in GUI clients. That was wrong, and the claim is not in this branch. npm gates the install-confirmation prompt on stdin.isTTY (libnpmexec/lib/index.js: if (noTTY() || ciInfo.isCI)), and an MCP stdio server always has piped stdin, so the prompt branch is unreachable. -y still earns its place: it matches the generated manifests, silences npx's warning, and protects users whose npm is configured yes=false, which hard-fails outright. It is a Changed, not a Fixed.

Verification

• lint, fmt:check, validate:server-json, and the full suite (1579 tests) pass; sync-manifests.cjs leaves the tree clean.
• The release sequence was exercised end to end in a scratch clone (sync-manifests → promote-changelog → git add) against a simulated version bump: exit 0. The sync's write targets were diffed against the version script's staging list in both directions — exact match, so no manifest can be synced and left uncommitted.
• Every table row was verified against that client's current documentation. Cline was dropped: its docs give a path only for the CLI, not the VS Code extension, so a row would have misdirected extension users. The VS Code user-level path is deliberately not stated, because VS Code documents no cross-platform path; the row names the MCP: Open User Configuration command instead.
• Badge payloads decode to the canonical configuration and are byte-identical across every commit that moved them.

Follow-ups (not in this PR)

• The sync/stage invariant is unenforced. package.json's git add list duplicates the targets array in sync-manifests.cjs with nothing linking them. Removing a target fails loudly; adding one and forgetting the list fails silently, shipping a release where a manifest is synced but never committed. A guard inside the script would close it.
• Plugin installs cannot set CONFIG. plugins/mediawiki-mcp-server/.mcp.json declares no env, so a user who installs via the Claude Code or Codex plugin has no documented way to point the server at their own wiki. That is the smoothest install path and the one a non-technical user is most likely to take.
• Generating the encoded payloads remains deferred, with a named trigger: build it if the encoded payload count exceeds four, or if drift recurs.

Considered and omitted: restoring code --add-mcp (it embedded an inline copy of the launch configuration, which is what this PR removes); per-client documentation files (the snippet is identical across clients, so it would turn one drifting file into nine); a hosted install page; and any restructuring around registries, whose own documentation disclaims being a client-facing install layer.

🤖 Generated with Claude Code