fix(remote): address review feedback on omp/claude respawn continuity

- Remote omp command now renders through buildSpawnCommandFromRegistry
  (the mode-agnostic engine local/docker spawns use) instead of the
  buildOmpCommand() the CLI-registry refactor deleted.
- Session._pinOmpRespawnId()/_maybeCaptureOmpSessionId() now skip
  host-local ~/.omp resolution entirely for a remote session and fall
  back to --continue: that resolver only ever reads THIS host's
  filesystem, which is meaningless (and could wrongly alias an
  unrelated local conversation) for a conversation that lives on the
  remote host.
- Remote-claude launch now honors an explicit resumeSessionId distinct
  from sessionId (mirrors claudeDockerPaneCommand's shape), and
  validates sessionId the same way that sibling does before
  interpolating it into the remote shell command.
- Add the still-missing header-cwd half of the trailing-slash test,
  and document respawn/reattach continuation + auto-reconnect-vs-
  clean-exit in docs/remote-sessions.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

test/omp-session-resolver.test.ts

@@ -20,7 +20,11 @@ import { mkdirSync, rmSync, utimesSync, writeFileSync } from 'node:fs';
 import { homedir } from 'node:os';
 import { join } from 'node:path';
 import { afterEach, describe, expect, it } from 'vitest';
-import { findLatestOmpSessionId, mangleOmpWorkingDir } from '../src/utils/omp-session-resolver.js';
+import {
+  findLatestOmpSessionId,
+  mangleOmpWorkingDir,
+  resolveAndClaimOmpSessionId,
+} from '../src/utils/omp-session-resolver.js';
 import { resolveOmpConfigForCreate } from '../src/web/routes/session-routes.js';
 
 describe('mangleOmpWorkingDir', () => {
@@ -78,6 +82,33 @@ describe('findLatestOmpSessionId', () => {
   });
 });
 
+describe('resolveAndClaimOmpSessionId: header-cwd trailing-slash normalization', () => {
+  // Sibling of the directory-mangle trailing-slash regression above, but for
+  // the OTHER half of the same fix: resolveAndClaimOmpSessionId additionally
+  // verifies each candidate file's own header `cwd` against workingDir (the
+  // mangle is lossy, so the filename-derived id alone isn't enough — see the
+  // function's doc comment). A remote case's workingDir carries a trailing
+  // slash (e.g. `/home/user/dotfiles/`) but omp's header `cwd` never does;
+  // without stripTrailingSlash() on BOTH sides of that comparison, a real
+  // on-disk session would be found by directory but rejected by the cwd
+  // check, silently degrading pinning to the ambiguous `--continue`.
+  const workingDirNoSlash = join(homedir(), 'dotfiles');
+  const workingDirWithSlash = `${workingDirNoSlash}/`;
+  const sessionDir = join(homedir(), '.omp', 'agent', 'sessions', '-dotfiles');
+
+  afterEach(() => {
+    rmSync(join(homedir(), '.omp'), { recursive: true, force: true });
+  });
+
+  it('matches a header cwd with no trailing slash against a workingDir that has one', () => {
+    mkdirSync(sessionDir, { recursive: true });
+    const header = `${JSON.stringify({ type: 'session', id: 'remote-dotfiles-uuid', cwd: workingDirNoSlash })}\n`;
+    writeFileSync(join(sessionDir, '2026-08-29T00-00-00-000Z_remote-dotfiles-uuid.jsonl'), header);
+
+    expect(resolveAndClaimOmpSessionId(workingDirWithSlash)).toBe('remote-dotfiles-uuid');
+  });
+});
+
 describe('resolveOmpConfigForCreate', () => {
   // The exact pipeline "resume this OMP row from the history list" drives:
   // POST /api/sessions with mode:'omp' + ompConfig:{continueSession:true}