feat(commands): whole-history dedupe + switchable, capped history

历史命令去重从「只跟最新一条比」改为「全历史去重」：重敲任意一条已有命令
时把原条目提到最前（刷新 lastUsedAt）而不是新插一条，历史里每个命令只出现一次。

新增两个设置（设置 → 终端）：
- 记录命令历史：关闭后不再记录新命令；已有历史保留，不清空
- 历史条数上限：默认 100，可配 1..500；写入按上限截断，读取也按当前
  上限截断（调低立即生效）

顺修一个暴露的既有 bug：logWrite 用 async appendFile，两次快速追加会
乱序落盘（line two 先于 line one）。改为按文件串行化追加。

测试：tests/commands-store.mjs 全历史去重 / 提到最前 / 上限生效 /
开关关闭不记录 / 关闭保留已有 / 恢复记录 / 越界上限夹紧，全部通过。

tests/commands-store.mjs

@@ -6,10 +6,11 @@
  * session log write/read/index behavior against a temp userData dir.
  *
  * Build: npx esbuild src/main/commands.ts --bundle --platform=node --format=cjs \
- *        --outfile=tests/.commands-store.cjs --alias:electron=./tests/electron-stub.cjs
+ *        --outfile=tests/.commands-store.cjs --alias:electron=./tests/electron-stub.cjs \
+ *        --alias:@shared=./src/shared
  * Run:   node tests/commands-store.mjs   (must exit 0)
  */
-import { mkdtempSync, readFileSync } from 'fs'
+import { mkdtempSync, readFileSync, writeFileSync } from 'fs'
 import { join } from 'path'
 import { tmpdir } from 'os'
 import { createRequire } from 'module'
@@ -25,16 +26,23 @@ const ok = (cond, msg) => {
 }
 const wait = (ms) => new Promise((r) => setTimeout(r, ms))
 
-// ---- 1. Bundle the store once (assumes tests/.commands-store.cjs exists) -------
+// ---- 1. Temp userData must exist before the bundle loads ------------------------
+// The settings store resolves its own path via app.getPath('userData'). The stub
+// is bundled *into* the module under test, so requiring it here gives a different
+// instance — `__setUserData` would not reach the bundle. The env var is read when
+// the stub loads, so it has to be set before the bundle is required below.
+const userData = mkdtempSync(join(tmpdir(), 'm5-cmd-'))
+process.env.OT_STUB_USERDATA = userData
+
+// ---- 1b. Bundle the store once (assumes tests/.commands-store.cjs exists) ------
 let commandsMod
 try {
   commandsMod = require_('./.commands-store.cjs')
 } catch {
-  fail('bundle not found — run: npx esbuild src/main/commands.ts --bundle --platform=node --format=cjs --outfile=tests/.commands-store.cjs --alias:electron=./tests/electron-stub.cjs')
+  fail('bundle not found — run: npx esbuild src/main/commands.ts --bundle --platform=node --format=cjs --outfile=tests/.commands-store.cjs --alias:electron=./tests/electron-stub.cjs --alias:@shared=./src/shared')
 }
 
-// ---- 2. Temp userData; capture openDir target ----------------------------------
-const userData = mkdtempSync(join(tmpdir(), 'm5-cmd-'))
+// ---- 2. Store over the temp userData; capture openDir target -------------------
 let openedPath = null
 const store = new commandsMod.CommandsStore(userData, async (p) => {
   openedPath = p
@@ -53,23 +61,78 @@ store.recordCommand('ps aux')
 hist = store.listHistory()
 ok(hist.length === 3, 're-run of newest command is deduped (no new entry)')
 
-// Re-run an OLDER command -> it is NOT the newest, so it becomes a fresh front
-// entry (spec dedupes only against the newest entry) with blank-recency guard.
+// Re-run an OLDER command -> dedupe is over the whole history, so it moves the
+// existing entry to the front instead of adding a copy.
 store.recordCommand('echo hello')
 hist = store.listHistory()
-ok(hist.length === 4, 'older command re-run is a new front entry (dedupe is newest-only)')
-ok(hist[0].command === 'echo hello', 'older re-run lands at front')
+ok(hist.length === 3, 'older command re-run does NOT add a copy (whole-history dedupe)')
+ok(hist[0].command === 'echo hello', 'older re-run is hoisted to the front')
+// The hoisted entry keeps its original createdAt (it is the same command, not a new one).
+ok(new Set(hist.map((h) => h.command)).size === 3, 'history holds 3 distinct commands')
 
-// Cap: fill until well above 500 keeps only the newest 500.
-for (let i = 0; i < 520; i++) store.recordCommand(`cmd-${i}`)
+// A command used long ago stays single even after many others in between.
+for (let i = 0; i < 20; i++) store.recordCommand(`noise-${i}`)
+store.recordCommand('ls -la')
 hist = store.listHistory()
-ok(hist.length === 500, `history capped at 500 (got ${hist.length})`)
-ok(hist[0].command === 'cmd-519', 'newest filler at front')
+ok(hist.filter((h) => h.command === 'ls -la').length === 1, 'a command seen 20 entries ago is not duplicated')
+ok(hist[0].command === 'ls -la', 'and it is hoisted to the front')
 
-// Clear.
+// Clear before the cap test so the assertions below are exact.
 store.clearHistory()
 ok(store.listHistory().length === 0, 'clearHistory empties history')
 
+// ---- 3b. History limit + the recording switch -----------------------------------
+const writeSettings = (terminal) =>
+  writeFileSync(join(userData, 'settings.json'), JSON.stringify({ terminal, system: {} }), 'utf8')
+const DEFAULT_LIMIT = 100
+
+// The bundled default raises past the old hard cap of 500 only when configured;
+// out of the box the list is trimmed to the default limit.
+for (let i = 0; i < 150; i++) store.recordCommand(`filler-${i}`)
+hist = store.listHistory()
+ok(hist.length === DEFAULT_LIMIT, `history trimmed to the default limit of ${DEFAULT_LIMIT} (got ${hist.length})`)
+ok(hist[0].command === 'filler-149', 'newest filler at front')
+
+// Lower the limit -> takes effect immediately, without needing a new command.
+writeSettings({ historyLimit: 20 })
+hist = store.listHistory()
+ok(hist.length === 20, `lowered limit applies on read (got ${hist.length})`)
+
+// Raise it -> entries that survived the *disk* cap (the configured limit at write
+// time) become visible again, up to the new limit. Nothing was resurrected from
+// beyond the write-time cap; the write cap is the real bound on disk growth.
+writeSettings({ historyLimit: 50 })
+store.recordCommand('after-raise')
+hist = store.listHistory()
+ok(hist.length === 50, `raising the limit reveals still-stored entries (got ${hist.length})`)
+ok(hist[0].command === 'after-raise', 'new command recorded after raising the limit')
+
+// Nonsense / out-of-range limits fall back to something sane instead of throwing.
+writeSettings({ historyLimit: 0 })
+ok(store.listHistory().length === 1, 'limit 0 clamps to 1 rather than emptying history')
+writeSettings({ historyLimit: 99999 })
+ok(store.listHistory().length === 50, 'absurd limit is clamped to the hard ceiling')
+
+// The switch: recording stops, and existing history is preserved (not cleared).
+writeSettings({ historyLimit: 50, historyEnabled: false })
+const before = store.listHistory()
+store.recordCommand('must-not-be-recorded')
+store.recordCommand('must-not-be-recorded')
+hist = store.listHistory()
+ok(!hist.some((h) => h.command === 'must-not-be-recorded'), 'historyEnabled=false records nothing')
+ok(hist.length === before.length, 'turning the switch off keeps existing history intact')
+
+// Turning it back on resumes recording.
+writeSettings({ historyLimit: 50, historyEnabled: true })
+store.recordCommand('recorded-again')
+ok(store.listHistory()[0].command === 'recorded-again', 'historyEnabled=true resumes recording')
+
+// Default (keys absent from settings.json) records, matching a fresh install.
+writeSettings({})
+store.recordCommand('default-on')
+ok(store.listHistory()[0].command === 'default-on', 'absent switch defaults to recording')
+store.clearHistory()
+
 // ---- 4. Library CRUD + ordering ------------------------------------------------
 const a = store.saveLibraryItem({ command: 'ps aux', name: 'procs', note: 'show processes' })
 await wait(2) // createdAt has ms resolution; avoid a timestamp tie breaking the order assertion