Terminal renderer fix + configurable padding and smaller font sizes

[mai1015]

Summary

Two terminal-focused changes, atomically committed.

1. fix: shape non-ASCII terminal cells per-segment to preserve combining marks

The row combiner previously gave up on the entire row as soon as one span was non-combinable (wide CJK, multi-codepoint, or anything non-ASCII), forcing the whole row through the slower per-span path.

• combine_terminal_row_runs now collects maximal contiguous groups of 1:1 char-to-cell ASCII spans and merges each group into its own TerminalRowLine, returning only genuinely non-combinable spans as leftover. One wide cell no longer blocks the rest of the row from combining.
• TerminalTextRun now carries one TerminalTextSegment per originating cell (byte range + column + hash). Non-ASCII text is painted per cell instead of per Rust char, so a cell's base character and any combining marks (e.g. "á" as a + U+0301) shape as a single unit at the correct column. The previous char-based split displaced combining marks into the next column.
• ASCII text keeps the fast single-shape path; only non-ASCII segments iterate.
• TerminalPreparedRow.line: Option<_> → lines: Vec<_> to carry multiple combined lines per row.
• New unit tests cover combining-mark cells, per-cell segment bookkeeping under append_text, and combining around a non-combinable span.

2. feat: configurable terminal padding and smaller font sizes

• New terminalPadding setting (0-40 px), plumbed end-to-end: AppSettings, sanitize, defaults, SettingsSummary, the settings service (set_terminal_padding), desktop settings UI (new select row), and terminal_config_for_settings (Edges::all(px(padding))).
• Static terminal_config() padding default drops from 10 px → 0 px so the user setting is the sole source of truth (the desktop pane insets were already adding their own padding, this avoids double-counting).
• Minimum terminal font size drops 10 → 8 across the cycle list, numeric_string bounds, and the desktop picker (8..=28). Mobile gains 10.0 and 11.0 steps and its remote-pane insets shrink 12 → 4 to match the tighter desktop layout.
• Default terminal line-height multiplier 1.45 → 1.2 — the old value left oversized row gaps at the new smaller sizes.
• Refactor: runtime terminal settings service routes numeric-string clamping through a shared set_numeric_string helper.

Files

• apps/desktop/src/terminal/{renderer,grid_version,element}.rs — renderer fix
• apps/desktop/runtime/src/settings/**, apps/desktop/src/app/{settings,settings_actions,terminal_state}.rs, apps/desktop/src/terminal/config.rs — padding feature
• apps/mobile/lib/{models/remote_models.dart, widgets/components/remote_terminal_pane.dart}, apps/mobile/pubspec.lock — mobile alignment

Test plan

• Desktop: terminal renders ASCII rows correctly (no regression in the combine path).
• Desktop: CJK / wide cells keep grid alignment; combining diacritics stack on the base glyph.
• Desktop: change Terminal Padding in settings → applies live, persists across restart.
• Desktop: cycle font size reaches 8 and wraps back from 28 → 8.
• Mobile: font picker shows 10.0/11.0 steps; terminal pane insets look correct.

Notes

• Skipped two untracked items that do not belong in this PR: .omo/ (local agent session state) and docs/spec/changes/add-tailscale-transport-2026-07-05/ (a proposed but unrelated tailscale transport spec).

Ultraworked with Sisyphus

[dux-web]

感谢贡献!这个 PR 已经部分合入 main:

• 渲染修复(6a2edd6)已原样 cherry-pick 为 ebce9d4,保留你的作者署名。main 上的分支菜单/终端这段时间重构较多,唯一的冲突是我们后来给合并门槛加的 symbol 字体检查(Nerd Font/powerline 需要逐格绘制)——已把该条件迁移进你新的 combine_terminal_row_runs 分组判断,语义与两边都一致,208 个测试全绿。
• 第二个 commit 以「可选设置」形式采纳(0a14a20,已给你挂 Co-authored-by):terminalPadding(0-40,默认保持 10)、新增 terminalLineHeight(1.0-2.0,默认保持 1.45)、字号下限放宽到 8。默认外观不变,想要你提议的紧凑效果的用户在 设置 → 通用 → 终端 里调 1.2 / 0 / 8 即可,对已打开的终端实时生效。移动端的 inset/字号档位改动暂未带入(移动端独立发版,后续单独评估)。

由于是 cherry-pick + 重实现而不是分支合并,GitHub 不会自动标记 merged,这里手动关闭。再次感谢!