Add V154 OG migration + admin list-UI, breadcrumb and sidebar enhancements

[mdon]

What

Adds core migration V154, creating the two tables the phoenix_kit_og plugin needs:

• phoenix_kit_og_templates — reusable OG canvas designs (canvas JSONB, optional preview_image_uuid)
• phoenix_kit_og_assignments — binds a template to a module_key × scope_type × scope_uuid scope via a JSONB slot_mapping

Uniqueness is a partial-unique-index pair, so a NULL scope_uuid (module-wide default tier) and per-scope assignments don't collide; template_uuid cascades on delete. Bumps @current_version → 154 and adds the ### V154 moduledoc block.

Renumbered on rebase (V152 → V154). This branch was authored against V152, but upstream/main has since claimed V152 (Newsletters/CRM send-profile restructuring) and V153 (folder header default). The OG migration was rebased onto current main and renumbered to V154 — the next free slot. The chain is contiguous 1..154 with no gaps. The migration file (postgres/v154.ex), @current_version, the moduledoc block, and the up/down version markers ('154' / '153') were all updated to match.

Notes

• Idempotent (CREATE TABLE/INDEX IF NOT EXISTS, ADD COLUMN IF NOT EXISTS).
• Prefix-safe: uuid_generate_v7() calls are schema-qualified, matching V148/V149.
• CHANGELOG.md + mix.exs version bump intentionally left out for the maintainer to add at review.

Verification

• mix format --check-formatted ✓
• mix compile --warnings-as-errors ✓
• mix credo --strict ✓ (no issues, whole tree)
• prefix_migration_test.exs (the full-chain scratch-schema oracle) ✓ — applies V153→V154 cleanly, both OG tables created, marker → 154.
• Full suite: 42 failures, identical to clean upstream/main (verified by running the same suite on 3813638f after a DB reset — the rebase introduces zero new failures; the 42 are pre-existing owner-role-protected / flash-not-fetched harness issues unrelated to this branch).

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Also in this PR: admin list-UI & chrome enhancements (6 commits)

The components/JS work that backs the phoenix_kit_projects list-page overhaul, all reusable by any module. Rebased onto current main; two of the original commits (a search_toolbar form fix and a page_section forward) were dropped as redundant — upstream/main already carries equivalents.

Components (core/)

• search_toolbar: added an in-flight loading spinner driven by phx-change-loading (sibling selector, pure CSS) with a loading_indicator opt-out for client-instant contexts.
• bulk_actions_toolbar: new :trailing slot — far-right toolbar content (e.g. a view-mode switcher) rendered after the contextual Reorder/Delete/Clear buttons.

Admin layout / breadcrumb

• page_action: pages can declare %{icon, label, navigate} and get a compact action button in the header breadcrumb next to the page title — lets list pages drop their in-content header row entirely. Forwarded through layouts/admin.html.heex alongside the existing page_section / page_section_path crumbs.
• Active sidebar tabs now carry aria-current="page" (accessibility + a stable client-side marker).

JS (priv/static/assets/phoenix_kit.js)

• TableLocalSearch hook: client-instant row narrowing for search_toolbar tables — hides rows by a lowercase data-search haystack during the debounce window while the server result stays authoritative; inert when the row set is incomplete (data-local-search-enabled).
• AdminSidebarScroll: the admin menu keeps its scroll position across every navigation (live redirects rebuild the main container; cross-live_session navigation is a full reload). sessionStorage save with phx:page-loading-start/pagehide flushes; pre-paint restore via the hook on live redirects and DOMContentLoaded on full loads; falls back to centering the [aria-current="page"] link.

Verification

• mix precommit ✓ (format, compile --warnings-as-errors, credo --strict)
• Component tests: table_default_test.exs — includes pins for the spinner opt-out and aria-current.
• Browser-verified in the parent app across the Projects/Tasks/Templates admin pages at desktop + phone widths.

[ddon]

Bunch of conflicts @mdon

[mdon]

Conflicts resolved — rebased onto current main. The OG migration collided with your V152 (send-profiles) and V153 (folder header), so I renumbered it to V154 (next free slot; chain is contiguous 1..154). Two of my commits (a search_toolbar form fix and a page_section forward) dropped out as redundant since main already has equivalents.

Verified: prefix_migration_test applies V153→V154 clean on a fresh scratch schema, and the full suite shows 42 failures identical to clean main (3813638f) — zero new failures from the rebase. mergeStateStatus is now CLEAN.