V2/token optimization (#11)

* v2.0: token-optimization overhaul

Additive (backward-compatible flags):
- file_read: skeleton mode, strip (imports/license/block_comments),
  compact_line_numbers, 8-char etag with prefix-match compat
- ast_query: format=verbose|compact|location, pagination cursor
- file_search: cluster mode, pagination cursor
- lsp_query (references): compact output

Breaking (v2):
- Preambles removed; opt-in verbose=true restores
- edit_apply: response=count|diff|none, default count
- ping tool removed
- symbol_at/find_definition/find_references merged into lsp_query
- Tool descriptions trimmed -83%, help moved to filepuff://help/<tool>
- Batch file_read dedups by etag

Protocol:
- ResourceLink returned for file_read >64 KiB (force_inline override)
- OnAfterInitialize hook reads capabilities.experimental.filepuff
  for session defaults (default_format, default_max_results,
  default_cluster, compact_refs, line_numbers,
  resource_link_threshold)

* fix: drop --max-total-count from ripgrep args

The flag does not exist in stable ripgrep (confirmed up to 15.1.0 --
"unrecognized flag --max-total-count, similar flags that are
available: --max-count"). Every file_search call failed on hosts with
stock rg. --max-count is per-file, not a drop-in replacement, so rely
on the in-process truncation in parseOutput that was already the
documented safety net.

internal/server/integration_test.go

@@ -43,23 +43,7 @@ func Hello() string {
 
 	ctx := context.Background()
 
-	// Test 1: Ping tool (health check)
-	t.Run("ping", func(t *testing.T) {
-		req := mcp.CallToolRequest{}
-		result, err := srv.handlePing(ctx, req)
-		if err != nil {
-			t.Errorf("handlePing() error = %v", err)
-		}
-		if result == nil {
-			t.Fatal("handlePing() returned nil")
-			return
-		}
-		if len(result.Content) == 0 {
-			t.Fatal("handlePing() returned empty content")
-		}
-	})
-
-	// Test 2: File read
+	// Test: File read (ping removed — Change 3)
 	t.Run("file_read", func(t *testing.T) {
 		req := mcp.CallToolRequest{}
 		req.Params.Arguments = map[string]interface{}{
@@ -144,14 +128,8 @@ func TestMCPToolDiscovery(t *testing.T) {
 		t.Fatal("MCP server not initialized")
 	}
 
-	// Verify each expected tool works
-	ctx := context.Background()
-
-	// Test ping tool
-	pingReq := mcp.CallToolRequest{}
-	if _, err := srv.handlePing(ctx, pingReq); err != nil {
-		t.Errorf("ping tool failed: %v", err)
-	}
+	// Ping tool removed (Change 3 — MCP protocol has own liveness check).
+	// Tools verified via integration tests in TestIntegrationFileOperations.
 }
 
 // TestMCPErrorResponses tests error handling following MCP spec.