fix(mcp): SSE transport served only 6 tools — delegate to the canonical dispatch

[aguung]

What

Unifies MCP tool dispatch so the Streamable HTTP/SSE transport serves the same tools as stdio. Fixes wick_info (and 4 other tools) returning unknown tool over the shared loopback MCP.

Why

tools/call had two dispatchers:

• handleToolsCall (stdio + HTTP-JSON) — the complete switch: 11 tools.
• handleToolsCallSSE (Streamable HTTP/SSE) — its own switch handling only 6: wick_list/search/get/encrypt/decrypt/execute, with default → "unknown tool".

Clients that speak Streamable HTTP/SSE (e.g. the agent's shared loopback wick MCP) therefore got unknown tool: wick_info even though tools/list advertised it — while the stdio wick-agent served it fine. The tools missing from the SSE path:

• wick_info, ask_user, wick_list_providers, wick_skill_list, wick_skill_sync

This is exactly the reported symptom: wick_info failed on the shared (SSE) server but worked on the stdio one.

How

Collapse the SSE switch into a single delegation:

if p.Name == "wick_execute" {        // the only tool that needs SSE streaming
    h.sseWickExecute(sess, r, req, p, user, tagIDs)
    return
}
h.sseStaticTool(sess, func(buf *bufferingWriter) {
    h.handleToolsCall(buf, r, req)   // canonical switch → buffered → one SSE frame
})

• The previously-explicit static cases (wick_list/search/get/encrypt/decrypt) used sseStaticTool (run handler → buffer → one frame) — the delegation does the identical thing through the canonical switch, so they are unchanged.
• wick_execute keeps its streaming goroutine path (progress events + heartbeats).
• The tool switch now lives in exactly one place (handleToolsCall). Adding a tool there works on stdio, HTTP-JSON, and HTTP-SSE automatically — no second switch to keep in sync.

This also unblocks any future top-level tools (e.g. a wick_manager_* surface) from silently breaking over SSE.

Testing

• TestSSEDispatchDelegatesNonStreamingTools — wick_info over the SSE path returns its payload, not unknown tool (RED before the fix).
• TestSSEDispatchStillServesConnectorTools — wick_list (a previously-explicit SSE case) still returns the connector through the delegation — proves the collapsed cases aren't lost.
• Full internal/mcp suite: 78 tests pass. go build ./cmd/lab ., gofmt clean.