library: client modules end in -client, like protocols end in -protocol

display-client and input-client (files and module names), so a service,
its wire contract, and its client never share a name: `display` the
service, `display-protocol` the contract, `display-client` a program's
view of it. The nine consumers' imports and their packages' declared
lists follow (regenerated from the source scan); build-support's
module_homes table carries the new names.

system/services/display-demo/build.zig

@@ -9,7 +9,7 @@ pub fn build(b: *std.Build) void {
     const exe = build_support.userBinary(b, .{
         .name = "display-demo",
         .root_source_file = b.path("display-demo.zig"),
-        .imports = &.{ "display", "logging", "time" },
+        .imports = &.{ "display-client", "logging", "time" },
     });
     b.installArtifact(exe);
 }

system/services/display-demo/display-demo.zig

@@ -11,7 +11,7 @@
 //! is deliberately independent of the mouse.
 
 
-const display = @import("display");
+const display = @import("display-client");
 const time = @import("time");
 const logging = @import("logging");
 pub fn main() void {

system/services/display/build.zig

@@ -10,8 +10,8 @@ pub fn build(b: *std.Build) void {
         .name = "display",
         .root_source_file = b.path("display.zig"),
         .imports = &.{
-            "display", "display-protocol", "driver", "input", "ipc", "logging", "memory",
-            "scanout-protocol", "service", "thread", "time",
+            "display-client", "display-protocol", "driver", "input-client", "ipc", "logging",
+            "memory", "scanout-protocol", "service", "thread", "time",
         },
         .threaded = true, // real atomics/TLS (docs/threading.md)
     });

system/services/display/display.zig

@@ -17,11 +17,11 @@
 
 const std = @import("std");
 const ipc = @import("ipc");
-const input = @import("input");
+const input = @import("input-client");
 const Thread = @import("thread").Thread;
 const service = @import("service");
 const time = @import("time");
-const display = @import("display");
+const display = @import("display-client");
 const memory = @import("memory");
 const logging = @import("logging");
 const compositor = @import("compositor.zig");

system/services/input/build.zig

@@ -9,7 +9,7 @@ pub fn build(b: *std.Build) void {
     const exe = build_support.userBinary(b, .{
         .name = "input",
         .root_source_file = b.path("input.zig"),
-        .imports = &.{ "input", "input-protocol", "ipc", "logging", "process", "service" },
+        .imports = &.{ "input-client", "input-protocol", "ipc", "logging", "process", "service" },
     });
     b.installArtifact(exe);
 }

system/services/input/input.zig

@@ -23,7 +23,7 @@ const std = @import("std");
 const ipc = @import("ipc");
 const process = @import("process");
 const service = @import("service");
-const input = @import("input");
+const input = @import("input-client");
 const logging = @import("logging");
 const input_protocol = @import("input-protocol");