fix(core): Clarify persist behavior and harden grep and quick peek cleanup

[mhiro2]

Summary

• Clarify persistence fallback behavior and repeated setup expectations in the documentation
• Route Telescope extension warnings through the shared peekstack notification helper
• Improve grep failure messaging for ignore-file related errors and add regression coverage
• Limit quick peek auto-close to the active root window and preserve history/events on wipeout paths

Changes

• f189723 : docs(setup): clarify persist fallback and reload behavior
  • Clarified that persistence uses repository storage inside a git repository and falls back to cwd-based
    storage outside it
  • Documented what repeated setup() calls re-register and what existing popups, stacks, and history are
    not migrated in place
• 70c25a0 : fix(extension): use peekstack notify for telescope warnings
  • Unified Telescope extension warnings with the shared notification helper so warning formatting stays
    consistent with the rest of the plugin
• 091924d : fix(grep): explain ignore file failures
  • Added targeted warning messages for ripgrep failures that likely come from .gitignore, .ignore, or
    .rgignore issues
  • Added regression tests for failure-message formatting and the warning path used by grep.search
• e875c6d : fix(stack): scope quick peek closes and preserve wipeout history
  • Scoped quick peek auto-close handling to the active root window so unrelated ephemeral popups are not
    closed across splits
  • Preserved PeekstackClose, PeekstackHistoryPush, and history entries when popups are removed through
    buffer or origin wipeout paths
  • Added regression tests for multi-window quick peek cleanup and wipeout event/history handling
• 31bbbf7 : test(grep): stub rg availability in failure spec
  • Removed the grep failure spec's dependency on the real rg executable so the ignore-file warning path is
    exercised consistently in CI