docs: mention helpers4-common's automatic git-config self-heal across all dependent features

[baxyz]

Summary

Pure documentation release — no functional change to any feature's install.sh or runtime behavior. Every feature that dependsOn: helpers4-common gets the automatic git-config self-heal (from #75) transitively, but that was previously only documented on helpers4-common's own README — undiscoverable for anyone using, say, claude-dev without also knowing to go read helpers4-common's docs.

Scope

All 15 features with a direct dependsOn: "ghcr.io/helpers4/devcontainer/helpers4-common:1" (verified exhaustively: jq -e '.dependsOn["ghcr.io/helpers4/devcontainer/helpers4-common:1"]' across every src/*/devcontainer-feature.json):

angular-dev, auto-header, bitwarden-secrets-manager, claude-dev, dotfiles-sync, essential-dev, git-absorb, mistral-dev, nub, package-auto-install, peon-ping, playwright-dev, pnpm-store, shell-history-per-project, vite-plus.

For each:

• Description (devcontainer-feature.json): appended "Also includes helpers4's automatic git-config self-heal." — identical short phrasing everywhere, deliberately, since it's the exact same underlying mechanism.
• README: a consistent callout — "Also included automatically: helpers4-common's git-config self-heal — fixes a stale credential.helper or a missing SSH commit-signing key in ~/.gitconfig on every container attach, no setup required. You never add helpers4-common yourself; every helpers4 feature pulls it in." — placed right after each feature's intro paragraph. (dotfiles-sync already had a more detailed, feature-specific note covering the same ground from its own refactor(dotfiles-sync): make SSH key file sync opt-in, drop redundant path-fixing #76 work — only its description got the short addition, to avoid a redundant second callout.)
• Version History: a new entry marking this as documentation-only, no functional change.
• 12 of the 15 go 1.1.0 → 1.2.0 (they were already bumped once for the dependsOn migration itself, in refactor: migrate all features off inline helpers4-common bootstrap to dependsOn #72). essential-dev and bitwarden-secrets-manager go to 1.1.0 — they already depended on helpers4-common from their own first release, so this is their first bump for this specific reason. dotfiles-sync goes to 1.2.0 (its own 1.1.0 already covered the functional side in refactor(dotfiles-sync): make SSH key file sync opt-in, drop redundant path-fixing #76).

AGENTS.md's feature table updated to match.

Everything else (descriptions read naturally, no historical/implementation references leaking into the main body — that's what Version History is for) was reviewed while touching each file; none needed further changes beyond the addition itself.

Test plan

• jq empty on all 15 changed manifests
• Verified the dependent-feature list is exhaustive (grepped every manifest for the dependsOn key, not just the ones from memory — caught essential-dev, which predates the refactor: migrate all features off inline helpers4-common bootstrap to dependsOn #72 migration and wasn't in that batch)
• AGENTS.md's feature-table-matches-manifest-version check replicated locally, passes

🤖 Generated with Claude Code

[github-actions]

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All checks passed!

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📋 Pipeline Status

	Job	Status
✅	🧾 Conventional Commits	passing
✅	🔖 Version Bump	passing
✅	🧪 Feature Tests	passing
✅	🐚 ShellCheck	passing

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_{🤖 Generated by @helpers4 CI • 2026-09-07}