docs: correct dash style and attribution wording

[Freudator86]

Intent

Fix three text-only defects in the firstmate instruction surface that were found by the documentation gate of the fm-adopt-domain-modeling work on 2026-08-03 and deliberately deferred by the captain so that proposal stayed narrow and reviewable.

1. docs/arm-pretool-check.md and 2. docs/decision-hold-lifecycle.md each violated the plain-dash repo style rule owned by the firstmate-coding-guidelines skill ('Plain dash -, never an em dash'). The recorded line numbers (24 and 31) were known to be stale, so the task explicitly required verifying them rather than trusting them. Verified: the offending characters are now at line 28 in arm-pretool-check.md and still line 31 in decision-hold-lifecycle.md. Each file contained exactly one PAIRED em dash (two characters) wrapping a parenthetical, not a single dash. Both files were then swept for the whole em/en/figure/minus dash class (U+2010-U+2015, U+2212) and confirmed clean.

2. README.md line 253 (recorded as ~228) introduced the third-party attribution list with 'Third-party material, both from mattpocock/skills'. The list has grown to THREE entries (sea-chart, to-backlog, domain-modeling), so 'both' is a false statement. This was explicitly NOT a licensing problem - the attributions themselves are complete and correct - only a wrong word. The requirement was that the wording be true for three entries AND stay true if a fourth is added, so 'both' was changed to 'all' rather than to 'three': 'all' is count-independent and does not need editing again when the list grows.

Deliberate constraints on this task: no behaviour, script, or contract text changes of any kind. The diff is exactly three single-line prose edits across three Markdown files. The em-dash replacements preserve the surrounding sentence and its parenthetical structure verbatim apart from the two dash characters in each. No tests were added, because there is no behaviour here to assert - the changes are prose in human-facing documentation, and the plain-dash rule is a style convention in a skill, not an enforced check. The repo's one-sentence-per-line Markdown rule is preserved: no line was split or joined.

What Changed

• Replace paired em dashes with plain dashes in two instruction documents while preserving their parenthetical wording.
• Correct the README attribution introduction from “both” to the count-independent “all.”

Risk Assessment

✅ Low: The change is limited to exactly three intended single-line documentation corrections, preserves the surrounding prose and line structure, and introduces no source or lifecycle risk.

Testing

No baseline test output was supplied; targeted diff and semantic checks confirmed exactly three prose substitutions, preserved line counts, clean prohibited-dash scans, truthful count-independent attribution wording, and a clean worktree. The final excerpts provide direct reviewer-visible evidence; no screenshot was created because the changed surface is plain Markdown prose with no visual layout or UI behavior.

Evidence: Final user-facing documentation excerpts

arm-pretool-check.md: “The denial gives Claude reason-specific recovery guidance - drain, repair supervision through the two service scripts, and use fail-closed `bin/fm-teardown.sh` for completed tasks - per the contract…”

decision-hold-lifecycle.md: “The `hold` reopen guard reads the same archive with the opposite question - whether *any* archived entry under the identity already carries a resolution - so…”

README.md: “Third-party material, all from `mattpocock/skills` by Matt Pocock and used under the MIT licence:” followed by the three existing attribution entries.

Pipeline

Updates from git push no-mistakes

✅ **intent** - passed

✅ No issues found.

✅ **Rebase** - passed

✅ No issues found.

✅ **Review** - passed

✅ No issues found.

✅ **Test** - passed

✅ No issues found.

• git diff --stat 8725f8124d786b1f4cdbf54ab25153d40d8bb412..8ea25e89e86b531e4e1389fc8472ee1c9a5d05d0
• git diff --unified=3 8725f8124d786b1f4cdbf54ab25153d40d8bb412..8ea25e89e86b531e4e1389fc8472ee1c9a5d05d0 -- README.md docs/arm-pretool-check.md docs/decision-hold-lifecycle.md
• Focused Python semantic comparison of each target blob against its base blob, asserting the exact intended substitution was the only content change and line counts were preserved
• Focused Unicode scan of both documentation blobs for U+2010–U+2015 and U+2212
• Focused README attribution check confirming count-independent “all” introduces the three current entries
• Commit-scope check asserting exactly three changed files with one removed and one added line each
• git status --short

✅ **Document** - passed

✅ No issues found.

✅ **Lint** - passed

✅ No issues found.

✅ **Push** - passed

✅ No issues found.