feat(/dotfiles-sync): privacy gate for SSH fragments + 1P-backup check

[tieubao]

Summary

The /dotfiles-sync command was the upstream cause of PR #69's leak. New SSH fragments were classified as core/local/skip with no privacy review, so mac-mini-danang got committed plaintext to a public repo.

This PR closes the loop: privacy gate at detection time, four-way classification, and a notify-only check for *.local fragments that lack a 1P Secure Note backup.

What changed

Area	Before	After
Detection	Lists fragment names only	Tags each [clean] or [private] using a heuristic (.ts.net FQDN, IP in HostName, multi-segment internal hostnames, non-standard SSH port, purpose-revealing identity files)
Classification	core / local / skip (3-way)	core / local / private / skip (4-way). private → rename to *.local, create op://Vault/SSH config: <name>/notesPlain. Flagged-private must never go to core.
Backup status	SSH keys only	Adds parallel check for ~/.ssh/config.d/*.local fragments without a 1P Secure Note. Drops OP_SERVICE_ACCOUNT_TOKEN per S-49 so the lookup sees the full vault list.
Action table	"Track SSH configs → chezmoi add"	Same row gains a verification guard; new row "Back up SSH fragment privately" with the literal op item create command
Report	host1, host2, ...	host1 [clean] / host2 [⚠ private]

Mirror parity preserved between .claude/commands/dotfiles-sync.md (project) and home/dot_claude/commands/dotfiles-sync.md (user, deployed via chezmoi).

Heuristic smoke test

Tested on three synthetic fragments locally:

Fragment	Verdict
Host github / HostName github.com / Port 22	clean ✓
Host mini / HostName mac-mini-danang / IdentityFile ~/.ssh/id_ed25519	private ✓
Host weirdvps / HostName 45.32.53.122 / Port 52847 / IdentityFile id_ed25519_trading_vps	private ✓

Test plan

• Mirror parity (/usr/bin/diff returns 0)
• Heuristic regex compiles in grep -E (no PCRE lookaheads — earlier draft had (?!22$) and was fixed before commit)
• Three-fragment smoke test passes
• Real-world: next /dotfiles-sync invocation correctly flags any new SSH fragment

🤖 Generated with Claude Code