[vitaliyslion]

Summary

The extension now registers gortex mcp with Pi's built-in MCP (pi.registerMcpServer) and leaves the tool channel entirely to Pi. Its own stdio MCP client (src/mcp-client.ts), tool registration (src/tools.ts), shared state (src/state.ts) and the native_mcp setting are removed. The remaining native* identifiers are renamed (src/native.ts -> src/mcp.ts, isNativeGortexTool -> isGortexTool, and so on).

Behaviour without a tool channel:

• When no MCP connector is loaded (--no-mcp), the binary does not resolve, or Pi refuses the registration, nothing is registered (or the refusal is recorded) and the first turn tells the model graph tools are unavailable and why.
• A refused registration may mean another source already supplies a gortex server, so the first turn still waits for its tools and reports the refusal only if none appear.
• Read discipline is skipped once the first turn has waited and found no graph tools, so Pi's own tools are never blocked with nothing to use instead.
• The first-turn wait is 15 s, because Pi loads its MCP extension after file extensions and its own 10 s connect wait runs after ours.

Each session builds a fresh extension instance, so each registers once; the re-register and withdraw logic and the session_shutdown handler are gone.

Closes #33

Breaking change: Pi 1.0+ with its MCP extension loaded is required. native_mcp: false / GORTEX_NATIVE_MCP no longer select a fallback channel. Both Pi peer dependencies (pi-coding-agent, pi-tui) are now >=1.0.0.

Related issues:

• Give each gortex mcp child its own session object and a lifecycle state machine #22 becomes obsolete: it is entirely about the removed MCPStdioClient.
• Run the hook bridge asynchronously, with piped stdio and per-call guidance #24 item 3 (the own-client gortex_read alias reaching the hook), with its alias bullet and regression test, becomes obsolete. The rest of Run the hook bridge asynchronously, with piped stdio and per-call guidance #24 still applies.

Deferred, unchanged by this PR:

• gortex hook stderr can reach the TUI (Run the hook bridge asynchronously, with piped stdio and per-call guidance #24 item 1).
• Windows .cmd shims pass the binary check (On Windows, a .cmd or .bat gortex shim passes the binary check but the hook cannot run it #37).
• No test covers sanitizing a diff's path or content (Test that a diff's path and content are sanitized before they render #38).

Testing

• npm run check passes (typecheck + 136 tests)
• New behaviour has a suite that drives it through Pi's ExtensionRunner (see docs/tests.md)
• Tried by hand in Pi (pi -e /path/to/checkout), if user-visible

Manual runs on Pi 1.3.0 with gortex v0.64.8 (pi -ne -e builtin:mcp -e <checkout> --mode json -p ...):

• Normal start: briefing arrives, 21 mcp__gortex__* tools registered, Pi's read blocked and redirected to the graph tools.
• --no-mcp: the model is told MCP support is not loaded; Pi's read is allowed.
• GORTEX_BIN=/nope/gortex: the model is told the binary is missing; Pi's read is allowed.
• Duplicate registration (another extension registers gortex first): the turn waits for the tools and no false unavailable message appears.

Mutation checks confirmed the suites fail when the enforcement gate, the tools-from-elsewhere check, the settled gate, the refusal wait or the late session_start fix is reverted, and when a handler throws.

Checklist

• No runtime dependencies added
• README configuration table updated, if config changed
• docs/architecture.md updated briefly, only if a design decision changed
• Works on Windows paths and process spawning, if touching either