Migrate command execution to structured argv lists across the plugin, replacing shell-string command construction with `vim.system` argv execution. The runner API now exposes argv-based execution as the default path:
- `runner.execute_command` -> `runner.execute`
- `runner.execute_command_async` -> `runner.execute_async`
- `runner.execute_command_raw` -> `runner.execute_raw`
- `runner.execute_command_raw_async` -> `runner.execute_raw_async`
- `runner.execute_command_sync` was removed; use `runner.execute` and handle the result directly
BREAKING CHANGES:
- `cmd.new({ args = ... })` now requires `args` as `string[]` argv tokens, not a single string.
- `cmd.log({ ... })` now uses `raw_flags` as `string[]` for raw passthrough flags; `raw = "..."` is no longer supported.
- Direct users of `jj.core.runner` must migrate from the old `execute_command*` string helpers to the new argv-based `execute*` helpers.
Pass raw command arguments to the interactive floating terminal instead
of a shell-escaped string.
This fixes native `jj resolve` exiting immediately when opened without
an external tool.
Add first-class conflict resolution support to jj.nvim.
- add `jj.cmd.resolve` to run `jj resolve` in a floating terminal or via an
external tool
- add `:J resolve` with support for `-r/--revision`, `--tool`,
`--external/--ext`, and positional filesets
- integrate resolve into the log buffer with the `gr` mapping and optional
`resolve_strategies` picker
- add `utils.is_change_conflicted()` and avoid opening resolve when the
selected revision has no conflicts
- document resolve usage, config, and keymaps in the README
- add tests for resolve arg parsing and conflict detection helpers
