Closes#460, #461.
**#460 — YAML injection via unquoted skill/prompt filenames**
`generateDefaultConfig` extracted skill directory names and prompt file
names from user-supplied `body.Files` keys and wrote them directly into
YAML list items without quoting:
cfg.WriteString(" - " + s + "\n")
`validateRelPath` only blocks path traversal (`../`); it does NOT block
YAML control characters including newlines. On Linux, filenames can
contain newlines, so an attacker with any live workspace bearer token
could submit:
{"files": {"skills/legit\nruntime: malicious/SKILL.md": "# skill"}}
The generated config.yaml would then contain `runtime: malicious` as a
top-level YAML key, overriding the runtime for workspaces provisioned
from the template.
Fix: extract `yamlEscape` as a reusable local from the same
`strings.NewReplacer` already used for the `name` field (#221) and apply
it to both the `skills:` and `prompt_files:` list items, wrapping each
in double-quotes.
**#461 — Docker error details in ReplaceFiles 500 responses**
`ReplaceFiles` returned `fmt.Sprintf("failed to write files: %v", err)`
in two 500 paths, where `err` comes from Docker API calls and may include
internal container names, volume names, and daemon error messages.
Fix: log the full error server-side and return a static opaque string to
the caller.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
284fb26558