fix: write session logs as plain text instead of raw PTY soup

Recorded logs carried the raw stream: SGR colors, cursor moves,
synchronized-output markers, and every TUI redraw frame — unreadable in an
editor and far larger than the visible output (a short kimi session logged
21.5KB of which 4.4KB is text). A per-session sanitizer now strips ANSI
statefully across chunk boundaries, collapses carriage-return overwrites
(progress bars keep only their final text), and suppresses alternate-screen
frames with a marker line. Ink-style inline TUIs redraw in the normal
buffer and cannot be frame-collapsed without screen emulation; their
committed lines are preserved.

src/main/logSanitizer.ts

@@ -0,0 +1,147 @@
+/**
+ * Plain-text sanitizer for session logs.
+ *
+ * Raw PTY output is unreadable in a text file: SGR colors, cursor moves,
+ * synchronized-output markers — and for full-screen TUIs (vim, htop) every
+ * redrawn frame. For each logged session this filter:
+ *   1. strips ANSI escape sequences (CSI / OSC / single-char), statefully
+ *      across chunk boundaries (a sequence may split between two PTY chunks);
+ *   2. collapses carriage-return overwrites (progress bars, spinner lines)
+ *      keeping only the final text of the line — a `\r` directly followed by
+ *      `\n` is a line ending, not an overwrite;
+ *   3. drops output produced while the alternate screen is active (TUI
+ *      redraw frames), emitting one marker line per suppressed span.
+ *
+ * Note: inline TUIs that redraw in the *normal* buffer (Ink-based CLIs such
+ * as Claude Code / kimi) cannot be frame-collapsed without full screen
+ * emulation; their committed lines are preserved as-is.
+ */
+
+const MARKER = '\n──── [全屏界面(TUI)输出已省略] ────\n'
+
+type Mode = 'text' | 'esc' | 'esc-skip1' | 'csi' | 'osc' | 'osc-esc'
+
+/** Alt-screen toggles: CSI ? 1049|1047|47 h / l */
+const ALT_ON = /^\?(?:1049|1047|47)h$/
+const ALT_OFF = /^\?(?:1049|1047|47)l$/
+
+export class LogSanitizer {
+  private mode: Mode = 'text'
+  /** raw bytes of the escape sequence in flight (bounded: OSC can be long) */
+  private seq = ''
+  private alt = false
+  /** some output was suppressed since the last marker */
+  private altDirty = false
+  /** current line, not yet newline-terminated */
+  private line = ''
+  /** previous text char was \r — the next char decides ending vs overwrite */
+  private cr = false
+
+  /** Transform one raw chunk; returns the plain text to append ('' for none). */
+  push(data: string): string {
+    let out = ''
+    for (let i = 0; i < data.length; i++) {
+      const c = data[i]
+
+      // A pending \r: `\r\n` completes the line; anything else overwrites it.
+      if (this.cr) {
+        this.cr = false
+        if (c === '\n') {
+          out += this.emitLine()
+          continue
+        }
+        this.line = ''
+        // fall through and process c normally
+      }
+
+      switch (this.mode) {
+        case 'text':
+          if (c === '\x1b') {
+            this.mode = 'esc'
+            this.seq = ''
+          } else if (c === '\r') {
+            this.cr = true
+          } else if (c === '\n') {
+            out += this.emitLine()
+          } else if (c === '\t' || c >= ' ' || c === '\x7f') {
+            // printable + tab; DEL and C0 controls (bell etc.) are dropped
+            if (this.alt) this.altDirty = true
+            else this.line += c
+          }
+          break
+        case 'esc':
+          if (c === '[') this.mode = 'csi'
+          else if (c === ']') this.mode = 'osc'
+          else if (c === '(' || c === ')' || c === '#' || c === '%') this.mode = 'esc-skip1'
+          else this.mode = 'text' // single-character escape, consumed
+          break
+        case 'esc-skip1':
+          this.mode = 'text'
+          break
+        case 'csi':
+          if (c >= '@' && c <= '~') {
+            // the final byte is not part of `seq` — test the full sequence
+            const full = this.seq + c
+            if (ALT_ON.test(full)) {
+              this.alt = true
+            } else if (ALT_OFF.test(full)) {
+              this.alt = false
+              if (this.altDirty) {
+                this.altDirty = false
+                out += MARKER
+              }
+            }
+            this.seq = ''
+            this.mode = 'text'
+          } else if (this.seq.length < 1024) {
+            this.seq += c
+          }
+          break
+        case 'osc':
+          if (c === '\x07') this.mode = 'text'
+          else if (c === '\x1b') this.mode = 'osc-esc'
+          break
+        case 'osc-esc':
+          // ST is ESC \; a new ESC [ / ESC ] starts the next sequence
+          if (c === '\\') this.mode = 'text'
+          else if (c === '[') {
+            this.mode = 'csi'
+            this.seq = ''
+          } else if (c === ']') this.mode = 'osc'
+          else this.mode = 'text'
+          break
+      }
+    }
+    return out
+  }
+
+  /** Flush the pending partial line at log stop. */
+  flush(): string {
+    let out = ''
+    if (this.cr) {
+      this.cr = false
+      // A trailing \r at stop: treat as line ending rather than overwrite.
+      out += this.emitLine()
+    } else if (this.line && !this.alt) {
+      out += this.line
+      this.line = ''
+    }
+    if (this.altDirty) {
+      this.altDirty = false
+      out += MARKER
+    }
+    return out
+  }
+
+  /** Complete the current line: hand it out with a newline and reset. */
+  private emitLine(): string {
+    if (this.alt) {
+      if (this.line) this.altDirty = true
+      this.line = ''
+      return ''
+    }
+    const out = this.line ? this.line + '\n' : '\n'
+    this.line = ''
+    return out
+  }
+}