fix: keep refreshing after markets close - #22

The bug

Reported symptom: the menu bar showed a price from yesterday at 3pm.

Evidence from the live 1.5.0 install:

The rotation timer had survived all 44 sleep/wake cycles, so this was never a dead timer. The refresh timer was firing every 60 s and returning immediately:

if isTimerTriggered && !anyMarketActive { return }

anyMarketActive is derived from the cached marketState, and only a fetch can update marketState — so the gate blocked the one thing that could clear it. The first closed session latched refreshes off for the rest of the process lifetime. It would not have resumed when the US market reopened on Monday.

This fires every single day, not just at weekends: once Yahoo moves from POSTPOST to CLOSED, TickerBar is frozen until it is relaunched.

The fix

A closed market must slow the cadence, never stop it. The repeating timer plus skip-gate becomes a one-shot timer that re-arms itself after every fetch, so the cadence always reflects the state the last fetch actually observed and marketState is always re-read.

• Active session → the user's refresh interval.
• Everything closed → max(interval, 15 min). 96 fetches a day, and a reopening, holiday or half-day is picked up within 15 minutes with no relaunch.
• Fetch failed → retried after 5 s, 15 s, 60 s, capped by the cadence, then the cadence takes back over so an outage cannot become a hot loop.

Also fixed, since "always refreshing" needs them:

• Wake from sleep refreshes immediately via NSWorkspace.didWakeNotification and re-anchors the cadence, instead of showing pre-sleep prices until the next tick.
• Watchlist panel tops up quotes older than one interval as it appears.
• Both timers moved to .common run loop modes, so a refresh still lands while the panel is open — the menu-tracking run loop does not service .default-only timers.
• Both timers carry a tolerance, letting macOS coalesce their wakeups with other timers instead of waking the CPU alone. Correctness comes from re-arming after each fetch, not from firing on an exact second.
• Concurrent callers (timer, wake, panel, manual button) coalesce onto one in-flight fetch, so a wake landing on an overdue timer cannot double-fetch or double-fire price alerts.

Verification

• 6 new tests, 91 total, all passing. They pin the contract that a closed market yields a finite cadence rather than a skipped fetch, that the user's interval always wins when slower than the idle cadence, that an enabled extended session keeps the fast cadence, and that the backoff never retries slower than the cadence and expires back to it.
• Widget extension target builds (the other half of the CI gate).
• Smoke tested: ran the fixed build on a Sunday with every market closed and it fetched live data (SRAD $13.82 +1.3%) — under 1.5.0 the same state was the frozen one.