feat(assail): write a KYAML copy beside the sealed JSON report

CHANGELOG.adoc

@@ -2,6 +2,26 @@
 
 === [Unreleased]
 
+==== Added — `+assail --output-format kyaml+` writes a KYAML copy
+
+* With `+--output-format kyaml+` and `+--output report.json+`, `+assail+` writes
+`+report.kyaml+` beside the JSON report. The JSON stays the report of record: it
+is what `+--attest+` seals. `+--output+` must end in `+.json+` (any letter case),
+and no two of the files written (report, copy, and the `+--attest+` sidecar)
+may be the same file: a symbolic link at any of their paths, or two existing
+paths that are hard links to one file, is refused before anything is written.
+So is a path that exists but is not a regular file (a directory, say) or that
+cannot be looked up, such as a derived name over the filesystem's length limit.
+In this mode each file is written by renaming a finished temporary file into
+place (`+atomic_write::write_replacing+`, which also flushes the directory so
+the rename survives a crash), so a link swapped in after those
+checks is replaced rather than written through, and no reader sees a partial
+report. On Unix a replaced file keeps the old file's permission bits, and the
+temporary file is never more readable than the file it replaces; a new copy or
+sidecar takes the report's permission bits, so a private report's companions
+are private too.
+Other formats are unchanged for `+assail+`.
+
 ==== Fixed — KYAML keys holding a line separator
 
 * KYAML output now escapes U+2028 (LS) and U+2029 (PS) as `+\uXXXX+`, as it

Cargo.toml

@@ -42,6 +42,7 @@ sha2 = "0.11"
 hex = "0.4"
 getrandom = "0.4"
 walkdir = "2.5"
+same-file = "1.0"  # assail: refuse a KYAML copy that aliases the sealed JSON report
 toml_edit = { version = "0.23", default-features = false, features = ["parse"], optional = true }
 dirs = "7.0"
 ed25519-dalek = { version = "3.0", optional = true }

README.adoc

@@ -172,7 +172,7 @@ Globally applied flags let automation pipelines control verbosity, output format
 | Flag | Default | Description
 | `--report-view` | `Accordion` | Controls the presentation mode (`Accordion`, `Summary`, `Timeline`) that the CLI writes and that PanLL mirrors.
 | `--expand-sections` | `false` | Expands extra detail blocks in the formatted report.
-| `--output-format` | `json` | Chooses how saved reports are serialized: `json` (I-JSON/JCS), `yaml`, `kyaml` (the estate YAML dialect, byte-compatible with `yq -o kyaml`), `nickel` or `sarif`. The CLI reuses this when it writes PanLL exports or temporal diffs. `assail` always writes JSON.
+| `--output-format` | `json` | Chooses how saved reports are serialized: `json` (I-JSON/JCS), `yaml`, `kyaml` (the estate YAML dialect, byte-compatible with `yq -o kyaml`), `nickel` or `sarif`. The CLI reuses this when it writes PanLL exports or temporal diffs. `assail` always writes the JSON report (the one `--attest` seals); with `kyaml` it also writes a `.kyaml` copy beside it, so `--output` must name a `.json` file.
 | `--pivot` | `false` | Rotates the narrative axis for boards that expect events-first storytelling.
 | `--store` | unset | Directory where generated reports, exports, and artifacts should land.
 | `--quiet` | `false` | Suppresses informational log lines for automation.