feat(mcp): adopt mainstream server-qualified MCP tool naming

Research across 8 multi-server agent clients (Claude Code, Codex, Gemini
CLI, VS Code, Cline, Roo Code, Goose, OpenCode) showed all of them keep
the server namespace in model-facing MCP tool names; the RFC's premise
for raw names ("servers already prefix their tools") is false for the
official GitHub/filesystem/Sentry servers.

- Config: drop toolPrefix; require serverName ([A-Za-z0-9_-]{1,32}),
  duplicate serverName fails the later instance at load (per-root
  reservation, released on dispose)
- Names: always mcp__<serverName>__<rawName>; normalize to the DeepSeek
  64-char [A-Za-z0-9_-] contract with a deterministic 12-hex identity
  hash on lossy normalization; raw name is the only thing sent on the
  wire (tools/call)
- Sync: two-phase fetch/swap — fetch failure keeps the previous
  generation; a swap conflict rolls back the whole generation (never a
  partial set); duplicate raw names reject the tool list
- RFC: moved to implemented/ (status + skeleton rewritten per the
  format contract), naming design + tier-level test coverage recorded
- Tests: naming algorithm unit suite; keyless Streamable HTTP e2e
  against an in-process StreamableHTTPServerTransport (namespace
  discovery, execution, per-request auth headers); dotted-name
  normalization e2e via a new fixture tool

docs/config-catalog.md

@@ -365,6 +365,12 @@ export type Config = StdioConfig | StreamableHttpConfig
 export interface StdioConfig {
   /** Transport type: spawn a child process and communicate over stdio. */
   transport: 'stdio'
+  /**
+   * Stable local namespace for this server's model-facing tool names
+   * (`mcp__<serverName>__<rawName>`). Must match `[A-Za-z0-9_-]{1,32}` and be
+   * unique across live mcp-client instances.
+   */
+  serverName: string
   /** Executable to spawn. */
   command: string
   /** Arguments passed to the command. */
@@ -373,8 +379,6 @@ export interface StdioConfig {
   env: Record<string, string>
   /** Working directory for the child process. */
   cwd: string
-  /** Prefix prepended to each tool name before registration. */
-  toolPrefix: string
   /** Timeout per callTool invocation (ms). */
   toolCallTimeoutMs: number
 }
@@ -383,18 +387,22 @@ export interface StdioConfig {
 export interface StreamableHttpConfig {
   /** Transport type: connect to an MCP server over Streamable HTTP (SSE). */
   transport: 'streamable-http'
+  /**
+   * Stable local namespace for this server's model-facing tool names
+   * (`mcp__<serverName>__<rawName>`). Must match `[A-Za-z0-9_-]{1,32}` and be
+   * unique across live mcp-client instances.
+   */
+  serverName: string
   /** MCP server URL. */
   url: string
   /** Extra headers (e.g. auth tokens). */
   headers: Record<string, string>
-  /** Prefix prepended to each tool name before registration. */
-  toolPrefix: string
   /** Timeout per callTool invocation (ms). */
   toolCallTimeoutMs: number
 }
 ```
 
-Source: [`packages/mcp/mcp-client/src/index.ts:66`](../packages/mcp/mcp-client/src/index.ts)
+Source: [`packages/mcp/mcp-client/src/index.ts:91`](../packages/mcp/mcp-client/src/index.ts)
 
 ## `@deepseek-ai/dsh-session-persistence-jsonl`