fix: skip update check (not just cache write) when config dir is absent (Bugbot #397)

[shujaatTracebloc]

Resolves a Cursor Bugbot finding on the cli promotion PR (#397, develop → main) — a follow-up to #404.

Update check unthrottled without config dir (Medium) — #404 correctly stopped writeUpdateCache from recreating a wiped ~/.tracebloc, but latestReleaseVersion still called fetchLatestRelease whenever the cache couldn't be read. On a fresh install (or after offboard) the config dir is absent, so the throttle cache can never be persisted — meaning every TTY command re-hit the GitHub releases API and could burn the full updateCheckTimeout, defeating the once-a-day throttle the failed-fetch path preserves elsewhere.

Fix (reconciles both #404 and this): a single configDirExists gate answers "can the update-check throttle be persisted?" and is now used by both sides:

• writeUpdateCache skips the write when the dir is absent (never resurrect a wiped dir — fix: Bugbot findings from promotion PR #397 (TLS floor + delete cache) #404). Unchanged behavior, refactored onto the shared gate.
• latestReleaseVersion skips the network check entirely when the dir is absent (nothing to persist, nothing to nudge — the CLI isn't set up or was offboarded), so it no longer hammers the API unthrottled (Release develop → main #397).

The distinction the finding asked for:

• dir absent → skip the fetch (return "").
• dir present but cache stale/unreadable → falls through to the normal throttled fetch + persist, so the everyday path is untouched.

Coverage added (reusing the existing httptest + temp-TRACEBLOC_CONFIG_DIR scaffolding), no existing tests removed:

• TestLatestReleaseVersion_MissingConfigDirSkipsNetwork — absent dir ⇒ no fetch attempted (test server errors if hit) and the dir is not created. Fails on the pre-fix code, passes with it.
• TestLatestReleaseVersion_DirPresentNoCacheFetchesAndPersists — dir present, no cache ⇒ still fetches and persists the throttle (guards the normal path).

(#397 (comment))

Lands on develop; the promotion PR head picks it up on the next sync and Bugbot re-reviews.

🤖 Generated with Claude Code

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Note

Low Risk
Best-effort CLI update nudge only; behavior is tighter throttling and no config-dir side effects, with new httptest coverage.

Overview
Fixes unthrottled GitHub release checks when ~/.tracebloc is missing (fresh install or after offboard). After #404 stopped writeUpdateCache from recreating the config dir, latestReleaseVersion could still call fetchLatestRelease on every TTY command because the throttle could never be saved—each run could hit the full updateCheckTimeout.

A shared configDirExists gate now answers whether the throttle can be persisted: latestReleaseVersion returns "" and skips the network when the dir is absent; writeUpdateCache uses the same helper (behavior unchanged from #404). When the dir exists but the cache is stale or missing, the normal once-per-day fetch and persist path is unchanged.

Tests cover absent-dir (no HTTP, dir not created) and dir-present-with-no-cache (fetch + cache write).

^{Reviewed by Cursor Bugbot for commit 214ca84. Bugbot is set up for automated code reviews on this repo. Configure here.}