refactor(edit): remove auto-indentation and add line-ending normalization

- [x] Remove auto-indentation from text mode edits (caller controls whitespace)
- [x] Add line-ending detection and normalization for both AST and text modes
- [x] Share edit logic via new `spliceContent` function for both modes
- [x] Fix diff to emit "No newline at end of file" markers
- [x] Fix diff to strip raw CR from CRLF file output
- [x] Remove double-unescape of backslash sequences in new_content
- [x] Fix countDiffLines to be hunk-aware (correctly count lines starting with +/-)
- [x] Fix block-comment stripping to remove standalone lines cleanly
- [x] Fix Python license header stripping to preserve separator blank lines

internal/parser/strip_newline_test.go

@@ -0,0 +1,47 @@
+package parser
+
+import (
+	"testing"
+
+	"github.com/lukaszraczylo/mcp-filepuff/pkg/protocol"
+)
+
+// An inline block comment (code before it on the same line) must not cause the following
+// line to be merged onto it — the line's terminator must survive.
+func TestStripBlockCommentInlineNoLineMerge(t *testing.T) {
+	got := StripContent("a := 1 /* note */\nb := 2\n", []StripFlag{StripBlockComments}, protocol.LangGo)
+	want := "a := 1 \nb := 2\n"
+	if got.Content != want {
+		t.Fatalf("inline block comment must not merge lines.\nwant: %q\ngot:  %q", want, got.Content)
+	}
+}
+
+// A standalone block-comment line (only whitespace before it) is removed in full,
+// including its indentation and terminator — no stray blank/whitespace line left behind.
+func TestStripBlockCommentStandaloneRemovesLine(t *testing.T) {
+	got := StripContent("x\n\t/* c */\ny\n", []StripFlag{StripBlockComments}, protocol.LangGo)
+	want := "x\ny\n"
+	if got.Content != want {
+		t.Fatalf("standalone block comment line must be removed cleanly.\nwant: %q\ngot:  %q", want, got.Content)
+	}
+}
+
+// On a CRLF file, removing a standalone block-comment line must consume the full \r\n
+// terminator rather than leaving a stray blank (bare-CR) line.
+func TestStripBlockCommentCRLFNoStrayBlank(t *testing.T) {
+	got := StripContent("code\r\n/* c */\r\nmore\r\n", []StripFlag{StripBlockComments}, protocol.LangGo)
+	want := "code\r\nmore\r\n"
+	if got.Content != want {
+		t.Fatalf("CRLF standalone block comment must not leave a stray blank line.\nwant: %q\ngot:  %q", want, got.Content)
+	}
+}
+
+// Stripping a hash-style license header must not greedily swallow the blank separator
+// line that follows it.
+func TestStripLicensePythonPreservesSeparatorBlank(t *testing.T) {
+	got := StripContent("# Copyright 2024\n# License MIT\n\ncode\n", []StripFlag{StripLicense}, protocol.LangPython)
+	want := "\ncode\n"
+	if got.Content != want {
+		t.Fatalf("python license strip must keep the blank separator.\nwant: %q\ngot:  %q", want, got.Content)
+	}
+}