docs: surface the user-visible reliability backlog in the roadmap

[flamerged]

Summary

Course correction on PR #24. I was too strict on "user-facing only" — a bunch of the Round-M items I'd parked in private memory are actually user-visible bugs (uploads hang, screenshot bursts dropped, slow upload misses next poll, typo'd commands silently run setup, fatal errors exit 0). Those belong in the public roadmap.

This PR:

1. Splits `## Roadmap` into two subsections — Reliability fixes and Features and ergonomics — so the list stays scannable.
2. Pulls 11 user-visible bug-class items out of memory into the Reliability subsection.
3. Leaves purely-internal items (commitlint config doc, semantic-release idempotency wiring, package.json metadata cleanup, CI smoke checks, monitor.ts split, tsconfig test/ inclusion) in memory — those are housekeeping, not user direction.

Items added under Reliability fixes

• SSH upload `BatchMode=yes` + timeout + EPIPE handler
• `sshshot stop` honors the 5 s graceful-shutdown window
• Decouple poll loop from upload completion
• macOS screenshot burst handling (oldest-first)
• `sshshot config` preserves `activeTarget` + `paused`
• Typo'd CLI commands print error + exit 1
• Fatal CLI errors set non-zero exit code
• `loadConfig` shape validation + `saveConfig` atomic writes
• Cache clipboard-tool availability at startup
• `~/.ssh/config` parse defensiveness + `?` wildcard filter + dedup
• `removePidFile` only-if-still-ours guard

`docs:` only, no release fired.

Test plan

• yarn format:check
• CI matrix Node 20/22/24 green (no source changes)

[github-actions]

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