fix: preserve shell expansion data and per-action approval

[takeokunn]

Summary

• Preserve private-use Unicode and escaped data through parameter expansion, command substitution, assignments, and globbing.
• Expand glob patterns after joining quoted and unquoted fragments, including command names.
• Require approval for every assistant action; never automatically execute the next action, and invalidate approval after editing.
• Stop assistant initialization at the first invalid sidecar response.
• Align the installation examples, manual, and readiness documentation with v0.6.3 and the tested behavior.

Verification

• macOS aarch64, SBCL 2.6.0: 2,372 tests passed with zero skipped, failed, or errored.
• Native executable: 23 expansion cases passed, including escaped paths, private-use Unicode, nested substitution, and quoted glob fragments.
• Original release PTY harness: six checks passed across three executable sessions; all owned processes were cleaned up. The local wrapper supplies the helper search path used by the release package.
• All 19 dependency suites passed.
• Changed Lisp files passed paredit checks; the intended files passed the redacted secret scan and diff hygiene check.
• The PTY job-listing test now waits for the complete status-and-command output. Existing assertions and deadlines are retained, with a deterministic split-chunk regression test.

Hosted Linux flake, integration, coverage, and extracted release-bundle gates must pass before merge and release publication.