fix(rtl): 清除被工具反复注入到 .v 末尾的 README 残行; 新增 RTL 文本自检脚本

- cpu21_pointer.v / cpu21_ps2_mouse.v / cpu21_vga.v 末尾多出一行 README 正文
  (Tcl ...), 会导致 Vivado: ERROR: [Synth 8-2715] non-printable character 0xe4
- 新增 pipelined-cpu/tools/check_rtl_text.ps1: 综合前秒级自检, 检出代码位置上
  的非 ASCII 文本/粘贴进来的正文行

pipelined-cpu/srcs/board/cpu21_board_top.v

@@ -345,7 +345,7 @@ generate
                             .ps2_data_i   (ps2_data),
                             .ps2_data_oe_o(),
         Tcl 一键重建
-            .ev_valid_o   (ev_valid),
+valid_o   (ev_valid),
                             .ev_dx_o      (ev_dx),
                             .ev_dy_o      (ev_dy),
                             .ev_btn_o     (ev_btn),

pipelined-cpu/srcs/rtl/cpu21_pointer.v

@@ -103,4 +103,3 @@ module cpu21_pointer #(
 endmodule
 
 `default_nettype wire
-Tcl 一键重建

pipelined-cpu/srcs/rtl/cpu21_ps2_mouse.v

@@ -142,4 +142,3 @@ module cpu21_ps2_mouse (
 endmodule
 
 `default_nettype wire
-Tcl 一键重建

pipelined-cpu/srcs/rtl/cpu21_vga.v

@@ -239,4 +239,3 @@ module cpu21_vga #(
 endmodule
 
 `default_nettype wire
-Tcl 一键重建

pipelined-cpu/tools/check_rtl_text.ps1

@@ -0,0 +1,77 @@
+# =============================================================================
+# check_rtl_text.ps1 —— detect stray non-Verilog text in the RTL sources.
+#
+# WHY: this project's .v files were twice corrupted by a text tool that inserted a
+# line of README prose into them ("Tcl ..." / a Chinese sentence), which made
+# Vivado fail with
+#     ERROR: [Synth 8-2715] syntax error near "..."  'non-printable character 0xe4'
+# and produced a cascade of bogus errors in the included ROM .vh. Running this
+# script takes a second and catches it before spending a synthesis run.
+#
+# WHAT IT CHECKS
+#   1) a line inside .v/.vh/.xdc that has non-ASCII characters *outside* a comment
+#      (i.e. real code position) -> corruption;
+#   2) a line that looks like pasted prose/markdown (leading "|", "**", or a line
+#      that is bare text after `endmodule`).
+#
+# USAGE (from the repository root or from pipelined-cpu/):
+#   powershell -ExecutionPolicy Bypass -File pipelined-cpu\tools\check_rtl_text.ps1
+# Exit code 0 = clean, 1 = found something.
+# =============================================================================
+$ErrorActionPreference = 'Stop'
+
+$srcs = Join-Path (Split-Path -Parent $PSScriptRoot) 'srcs'
+if (-not (Test-Path $srcs)) { Write-Output "ERROR: cannot find $srcs"; exit 2 }
+
+$bad = 0
+$files = Get-ChildItem -Recurse -Path $srcs -Include *.v, *.vh, *.xdc -File
+
+foreach ($f in $files) {
+    $rel = $f.FullName.Substring($srcs.Length).TrimStart('\', '/')
+    $lines = @(Get-Content -LiteralPath $f.FullName)
+    $inBlockComment = $false
+
+    for ($i = 0; $i -lt $lines.Count; $i++) {
+        $line = $lines[$i]
+        $lineNo = $i + 1
+
+        # ---- strip comments so we only look at code positions ----
+        $code = $line
+        if ($f.Extension -eq '.xdc') {
+            $h = $code.IndexOf('#'); if ($h -ge 0) { $code = $code.Substring(0, $h) }
+        }
+        else {
+            $c = $code.IndexOf('//'); if ($c -ge 0) { $code = $code.Substring(0, $c) }
+            if ($inBlockComment) { $code = '' }
+            if ($line -match '/\*') { $inBlockComment = $true }
+            if ($line -match '\*/') { $inBlockComment = $false }
+        }
+
+        $trim = $line.Trim()
+
+        # ---- check 1: non-ASCII in code position ----
+        if ($code -match '[^\x00-\x7F]') {
+            Write-Output ("!! $rel`:$lineNo  non-ASCII text in code position:")
+            Write-Output ("        " + $trim)
+            $bad++
+            continue
+        }
+
+        # ---- check 2: pasted prose / markdown leftovers ----
+        if ($trim -match '^\||^\*\*|^#[^0-9#]' -and $f.Extension -ne '.xdc') {
+            Write-Output ("!! $rel`:$lineNo  looks like pasted prose:")
+            Write-Output ("        " + $trim)
+            $bad++
+        }
+    }
+}
+
+Write-Output ""
+Write-Output ("scanned " + $files.Count + " files under srcs/")
+if ($bad -eq 0) {
+    Write-Output "RTL text check: OK (no stray non-Verilog text found)."
+    exit 0
+}
+Write-Output ("RTL text check: FAILED, " + $bad + " suspicious line(s) - fix them before synthesis.")
+Write-Output "Hint: such lines are usually injected by an editor/tool; remove them, then re-run this script."
+exit 1