feat: unify widget hiding into a single hideable-state system

[zachthedev]

Closes #428 (my proposal from earlier today; happy to rework or split).

Nine per-widget hide keys (hideNoGit, hideNoJj, hideNoRemote, hideZero, hideWhenEmpty, hideIfDisabled, hideStatus, hideTitle, hideWhenNotFork) become one mechanism: widgets declare conditions via an optional getHideableStates(), enabled states live in metadata.hide as a comma-separated list, and a shared (h)ide… keybind opens a checklist for the selected widget.

Diff guide (121 files): ~55 widget files are the same mechanical conversion; most test changes are one-line key swaps.

Group	Files	What changed
Core	shared/hideable.ts (new), types/Widget.ts	state declarations + isHidden/get/set (~95 lines)
Migration	utils/migrations.ts, types/Settings.ts	v3 -> v4 converts legacy keys per widget type (hideNoGit also covered (no upstream) on Ahead/Behind and the no-PR placeholder on Git PR; on-disk git-pr alias handled); one test per mapping
TUI	HideStatesEditor.tsx (new), items-editor wiring	one injected h keybind opens the checklist
Renderer	utils/renderer.ts	merge-target-hidden pass: decorative custom-text/symbol items collapse with their merge target
Widgets	~55 files	drop the bespoke toggle, declare states, call isHidden()
Tests	~42 files	new: hideable/migration/renderer suites; existing: one-line key swaps
Docs	USAGE.md, AGENTS.md	new "Hiding Widgets Conditionally" section

Behavior:

• Existing configs render identically after migration
• Ahead/Behind's hardcoded 0/0 auto-hide becomes a default-enabled zero state, now opt-out-able
• New opt-in states: zero (token widgets, session cost/clock, git counters), no-data (speed widgets, Block Timer, Git CI Status' -, usage widgets' [No credentials]-style errors), default-value (Output Style)
• Reset timers are excluded from no-data: they bind h for the hour toggle; a registry test enforces the h reservation
• Instant h toggles become a checklist (Space toggle, Enter save)
• Downgrade: older versions ignore metadata.hide, so hidden placeholders reappear until upgrading back (in USAGE.md)
• Dropped the dead hide: z.boolean() from WidgetItemSchema; no updatemessage added since rendering is unchanged

Open question: stock Ahead/Behind items now show (hide: zero) in the editor since defaults are surfaced honestly. Want default-enabled states suppressed from that annotation?

Happy to split (core conversion / new states / renderer pass) in whatever order you prefer.

Rebased onto current main. The conversion covers every widget that landed while this was open, so nothing is left on the old per-widget flags:

• feat(compaction): add a metric selector for composable sub-values #457 (metric selector), the reconcile flagged in the merge-order note below: its metric mode now uses isHidden(item, ZERO_HIDEABLE_STATE.key) for per-metric hide-zero, and the h bind it added for metric mode returns to the shared checklist. Compaction Counter keeps only v in metric mode.
• Cache Timer (feat: add CacheTimer widget (continues #307) #466): hideWhenEmpty becomes the empty state, reusing CACHE_EMPTY_HIDEABLE_STATE so it matches the other cache widgets, with a cache-timer migration rule.
• GitHub CI Status (feat(widget): add github ci status #492): it imported shared/git-no-git, which this PR removes, so it declares NO_GIT_HIDEABLE_STATE now.
• Weekly Fable Usage (feat(widget): add Fable Weekly Usage widget #522): it had no hide handling, so it picks up the no-data state its sibling usage widgets declare.
• Cache Hit Rate / Cache Read / Cache Write keep the empty conversion, and Extra Usage Used the disabled state, from the earlier rebase.
• Git Branch and Git Root Dir keep the w max-width bind from ✨ feat(widgets): honor maxWidth in Git Branch and Git Root Dir #488 alongside the conversion; Git PR keeps s/t.

Tested: bun run lint clean; bun test 2064 pass, plus the one global-command-resolution failure main already has on this host (confirmed against a pristine main checkout). Exercised against my real config inside and outside repos.

Note: #347 (rules engine) reuses the hide: z.boolean() field this PR removes and adds rule-based hiding; if that lands first I'll rebase the schema change and align the hide semantics with it.

[sirmalloc]

@zachthedev Can you go ahead and rebase this on main and resolve any issues?

[zachthedev]

@zachthedev Can you go ahead and rebase this on main and resolve any issues?

Will do sometime in the next 24 hours

[zachthedev]

Rebased onto main, conflicts resolved. #431 had merged into the same Git/JJ widgets, so they now carry both symbol-override and hideable; also extended the conversion to the Cache and Extra Usage Used widgets that landed since, with v3 -> v4 migration. lint clean; bun test green bar the pre-existing Windows-env failures. Ready for review.

[zachthedev]

Merge-order note: #457 (Closes #450) also touches CompactionCounter hide-zero. It adds per-metric hide-zero on hideZero; this PR migrates hideZero to the unified system. Whichever merges second needs a small reconcile; if #457 lands first, this PR's conversion must also cover the metric mode.

[zachthedev]

@zachthedev Can you go ahead and rebase this on main and resolve any issues?

Ready for review. Thanks much!

[zachthedev]

Rebased onto current main, ten conflicts resolved. Conversion extended to what landed
while this sat open: #457's metric mode, #466's Cache Timer (hideWhenEmpty -> empty),
#492's GitHub CI Status, #522's Weekly Fable Usage. Their h binds go back to the shared
hide checklist, which owns h.

Four migration bugs, all fixed:

• git-ci-status had no V4_HIDE_FLAG_RULES entry. migrateItemHideFlags bails on
  unlisted types, so a v3 config lost hideNoGit and config.ts wrote it back at version
  4, so the pass never reruns. Shipped in v2.2.24.
• stateOrder doubles as the filter for the merged list, so a state missing from it was
  dropped. The seven git counters lost zero, the three Extra Usage widgets lost no-data.
• A type naming an Object.prototype member resolved through the object literal, passed
  the if (!rule) guard, then threw. Unhandled rejection on feat: add config import/export with preview and merge modes #427's import path, swallowed
  into default settings on load. Guarded with Object.hasOwn.
• A written hide list merged with defaultEnabled instead of replacing it, contradicting
  isHidden, where a present list is authoritative. {"hide":"","hideNoGit":"false"} undid
  an explicit opt-out.

One new state: Git CI Status declares no-data for its - placeholder, opt-in. It reads
the same cache as Git PR, so hiding Git PR's no-PR placeholder left a bare - beside it.

The old test sampled one widget per rule constant with no tie to the registry, which is how
these slipped. It now walks the registry and checks every widget declaring a hideable state,
plus a structural check of each rule against its widget. Each fix fails without it: 1 for
git-ci-status, 7 for the git counters, 3 for Extra Usage, 4 for the prototype types, 2 for
the authoritative-list change. Docs picked up the cache family and Weekly Fable Usage,
neither of which had a documented state key.

lint clean, bun test 2064 pass bar the global-command-resolution failure main has on
this host.