fix(cli): translate LF→CRLF in streaming sink to stop rendered drift

[emal-avala]

Diagnosis — print layer, not markdown

The drift you saw (every newline indented to the column where the previous line ended) is not a markdown rendering bug — markdown is never applied during streaming at all. It's a raw-mode terminal bug introduced by #106.

Since #106 landed `spawn_escape_watcher` to make Escape/Ctrl+C interrupt the agent, the watcher calls `crossterm::terminal::enable_raw_mode()` at the start of a turn and keeps it on until the turn completes. In raw mode a bare `\n` moves the cursor down one row without returning to column 0 — the tty layer no longer translates LF to CRLF for you. The streaming sink was still emitting `print!("{text}")` and `println!()` and `eprintln!(...)`, so every newline the LLM produced dropped the cursor onto the next row at the column where the previous line ended. Over a multi-paragraph reply the text walks off the right edge, which matches both examples you posted exactly.

The tui helpers (`render_tool_block`, `render_turn_summary`, `render_thinking_block`, `render_status_bar`) were already correct — they go through `render_lines_to_ansi` which writes `\r\n`. Only the raw `print!`/`println!`/`eprintln!` call sites inside `TerminalSink` and the turn-error branch in `run_repl` were broken.

Fix

Two private helpers at the top of `crates/cli/src/ui/repl.rs`:

• `raw_print(text)` — writes to stdout with LF → CRLF translation, flushes.
• `raw_eprint(text)` — same for stderr.

Both normalize any existing `\r\n` first so translation is idempotent (no `\r\r\n`). Bare `\r` (used by `ActivityIndicator` to rewrite the status line) passes through unchanged.

All eight `print!`/`println!`/`eprintln!` sites inside the raw-mode window now route through them:

• `TerminalSink::ensure_newline`
• `TerminalSink::on_text`
• `TerminalSink::on_tool_result` (both success and error branches)
• `TerminalSink::on_error`
• `TerminalSink::on_compact`
• `TerminalSink::on_warning`
• The turn-error branch in `run_repl`

Print sites outside the turn (setup wizard, shortcut panel, session summary, rustyline output) are untouched — they run in cooked mode.

Tests

Added a `raw_print_tests` module with 8 unit tests covering the translation table, including the two edge cases that matter:

• existing `\r\n` must not become `\r\r\n`
• bare `\r` must pass through (or the activity indicator stops rewriting in place)

```
running 8 tests
test ui::repl::raw_print_tests::existing_crlf_is_preserved_not_doubled ... ok
test ui::repl::raw_print_tests::bare_lf_becomes_crlf ... ok
test ui::repl::raw_print_tests::cr_followed_by_text_then_lf ... ok
test ui::repl::raw_print_tests::empty_string ... ok
test ui::repl::raw_print_tests::lone_cr_is_not_touched ... ok
test ui::repl::raw_print_tests::mixed_lf_and_crlf ... ok
test ui::repl::raw_print_tests::text_without_newlines_is_unchanged ... ok
test ui::repl::raw_print_tests::multiple_newlines_all_translated ... ok

test result: ok. 8 passed
```

Manual test plan

• `cargo run -p agent-code`, ask for a multi-paragraph reply (e.g. "explain what pwd does"), confirm the response renders flush-left with no drift.
• Run a turn that triggers a tool (`ls`, then a file read), confirm the tool blocks and result previews render flush-left.
• Trigger an error mid-turn (bad tool input), confirm the ERROR label is flush-left.
• Press Esc mid-stream to confirm fix: make Escape and Ctrl+C actually interrupt agent during streaming #106's interrupt behavior still works.
• Press Ctrl+C mid-stream to confirm cancellation path still works.

Followup not in this PR

The other bug visible in your first paste — where three successive prompts `pwd` / `ls` / `fetch ...` got concatenated into `/doctoepwdlsfetch latest origin/main` and fed as a single input — looks like a separate rustyline / input-buffer issue, not a rendering issue. Worth filing separately; happy to pick it up next.

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