refactor(process): split the process manager out of the bash executor

New process/ capability family: @deepseek-ai/dsh-process owns ctx.processes —
abstract ProcessManager.spawn(spec) over a fully-explicit ProcessSpawnSpec —
plus the shared DSH_* managed-environment and CollectedOutput vocabulary;
@deepseek-ai/dsh-process-local carries the former bash-local run.ts plumbing
(detached groups, tail-keep spill-backed output, credential scrub, kill
escalation, kill-and-join disposal) with no config of its own.

dsh-bash-local becomes a consumer: it keeps command defaulting, the fused
deadline timedOut/aborted classification, the model-friendly terminal env
(now merged through the ordinary env channel), and the [stderr]-marked
background read merge, and spawns through ctx.processes. Background-process
lifetime moves to the manager, so an executor reload no longer kills live
background work; a background spawn failure is injected once into the read
path instead of being buffered as fake stderr. dsh-bash re-exports the moved
vocabulary so bash consumers keep one import root; dsh-bash-sandbox only
redeclares the inherited inject.

Every composition loading a bash executor now loads dsh-process-local (CLI,
examples, python bundled runtime, create-sdk bash feature, inline test
configs).

packages/process/process-local/tests/manager.spec.ts

@@ -0,0 +1,70 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import LocalProcessManager from '@deepseek-ai/dsh-process-local'
+import type { ProcessSpawnSpec } from '@deepseek-ai/dsh-process'
+
+function spec(command: string, overrides: Partial<ProcessSpawnSpec> = {}): ProcessSpawnSpec {
+  return {
+    argv: ['bash', '-c', command],
+    cwd: process.cwd(),
+    stdoutMaxBytes: 64_000,
+    stderrMaxBytes: 64_000,
+    maxSpillBytes: 64 * 1024 * 1024,
+    graceMs: 200,
+    ...overrides,
+  }
+}
+
+describe('LocalProcessManager', () => {
+  it('registers as ctx.processes and spawns managed handles', async () => {
+    const ctx = new Context()
+    const fiber = await ctx.plugin(LocalProcessManager)
+    const result = await ctx.processes.spawn(spec('echo managed')).done
+    expect(result.exitCode).toBe(0)
+    expect(result.stdout.text).toBe('managed\n')
+    await fiber.dispose()
+  })
+
+  it('disposal kills still-running processes and awaits their exit', async () => {
+    const ctx = new Context()
+    const fiber = await ctx.plugin(LocalProcessManager)
+    const handle = ctx.processes.spawn(spec('sleep 60'))
+    await fiber.dispose()
+    const outcome = await handle.done
+    expect(outcome.signal).toBe('SIGTERM')
+  })
+
+  it('a settled process leaves the live set (disposal does not re-kill it)', async () => {
+    const ctx = new Context()
+    const fiber = await ctx.plugin(LocalProcessManager)
+    const handle = ctx.processes.spawn(spec('true'))
+    const outcome = await handle.done
+    expect(outcome.exitCode).toBe(0)
+    await fiber.dispose()
+  })
+
+  it('disposal tolerates a handle whose spawn already failed', async () => {
+    const ctx = new Context()
+    const fiber = await ctx.plugin(LocalProcessManager)
+    const handle = ctx.processes.spawn(spec('true', { cwd: '/nonexistent-dir-dsh-manager-test' }))
+    await expect(handle.done).rejects.toThrow()
+    await fiber.dispose()
+  })
+
+  it('disposal contains a spawn-failure rejection that races teardown', async () => {
+    const ctx = new Context()
+    const fiber = await ctx.plugin(LocalProcessManager)
+    // Dispose before the rejection continuation removes the handle from the
+    // live set, so teardown itself must swallow the rejected done.
+    const handle = ctx.processes.spawn(spec('true', { cwd: '/nonexistent-dir-dsh-manager-test' }))
+    await fiber.dispose()
+    await expect(handle.done).rejects.toThrow()
+  })
+
+  it('loading a second implementation throws (one processes service per context — cordis standard)', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LocalProcessManager)
+    class SecondManager extends LocalProcessManager {}
+    await expect(ctx.plugin(SecondManager)).rejects.toThrow(/service "processes" has been registered/)
+  })
+})