feat: add tags/labels for saved items

- Add free-form tags per item: chip display with remove, inline add (comma-separated, grid view only), and a toolbar tag-filter popover listing every tag in use
- Search now also matches tags; tags sync across devices like every other item field
- Fix Firefox manifest.json compliance for AMO submission: replace the placeholder gecko id with a real UUID, add the now-required data_collection_permissions (bookmarksInfo, since synced items are personal browsing/bookmark data), and bump strict_min_version to 140.0 (142.0 for gecko_android) to match
- Add description.md (elevator pitch / short / detailed descriptions for store listings), PRIVACY.md, and .gitignore for the dist/ packaging output
- Reword all em-dash punctuation across docs and code comments per user preference

README.md

@@ -1,12 +1,12 @@
 # Read it later
 
 A new-tab page that shows everything you've saved to read later, as a
-sortable grid or list. No account, no server — everything lives in your
+sortable grid or list. No account, no server: everything lives in your
 browser's local extension storage.
 
 ## How to save something
 
-- **Click the toolbar icon** — saves the page you're currently on.
+- **Click the toolbar icon**: saves the page you're currently on.
 - **Right-click a page** → "Save page for later"
 - **Right-click a link** → "Save link for later" (doesn't need to be open)
 
@@ -15,9 +15,9 @@ A ✓ briefly appears on the icon to confirm the save.
 ## The shelf (new tab page)
 
 - Toggle between **grid** (cards with thumbnails) and **list** (compact,
-  bookshelf-spine style) — top right.
+  bookshelf-spine style), top right.
 - **Sort** by newest, oldest, title, or site.
-- **Search** filters by title, domain, or URL as you type.
+- **Search** filters by title, domain, URL, or tag as you type.
 - **Archive** tucks an item away without deleting it; "Show archived"
   reveals archived items again.
 - **Delete** removes an item, with a 5-second **Undo**.
@@ -26,56 +26,68 @@ Thumbnails are captured automatically when you save the *current* page
 (a screenshot of what's on screen). Links saved via right-click show a
 favicon instead, since the browser hasn't loaded that page yet.
 
+## Tags
+
+In grid view, click **+ tag** on any card to add one or more free-form
+labels (comma-separated, e.g. `css, research`); click the **×** on a chip to
+remove it. Tags are grid-only: list view stays the compact bookshelf row
+it's meant to be.
+
+Click a tag chip (on a card, or in the 🏷 toolbar button's dropdown, which
+lists every tag currently in use) to instantly filter the shelf to it. This
+just fills in the search box, so typing a tag name works too, and it
+combines with everything search already matches (title, domain, URL).
+
 ## Reminders and auto-delete
 
 The gear icon opens a settings panel (also home to the light/dark/system
 theme picker) with two optional timers, both off by default:
 
-- **Remind me after** — items older than this get pinned to the top of the
+- **Remind me after**: items older than this get pinned to the top of the
   shelf and highlighted, so they don't get buried.
-- **Delete unarchived items after** — silently removes items you never
+- **Delete unarchived items after**: silently removes items you never
   came back to. Archiving an item takes it out of consideration entirely.
 
-The delete period must be longer than the reminder period — enforced both
-in the settings panel (an inline error if you try to set it shorter) and as
-a hard rule in the deletion logic itself, so you're always warned before
-anything is removed. Auto-delete runs on an hourly background alarm (so it
-still works even if you never open the new tab page), and again whenever
-the shelf page is open; when the shelf page does the deleting, it shows a
-courtesy toast with an **Undo**.
+The delete period must be longer than the reminder period. This is
+enforced both in the settings panel (an inline error if you try to set it
+shorter) and as a hard rule in the deletion logic itself, so you're always
+warned before anything is removed. Auto-delete runs on an hourly background
+alarm (so it still works even if you never open the new tab page), and
+again whenever the shelf page is open; when the shelf page does the
+deleting, it shows a courtesy toast with an **Undo**.
 
 ## Worth a second look
 
 Above the shelf, a small strip proactively surfaces 2–3 old, forgotten,
-unarchived items each time you open a new tab — on by default, toggleable
+unarchived items each time you open a new tab, on by default and toggleable
 in the settings panel. Unlike a notification, it doesn't nag: the more
 times an item gets shown without you opening/archiving/deleting it, the
 less often it's picked again (backing off from every few days out to every
 couple of months), so nothing gets shown forever, but nothing gets shown
 *so* rarely that it's effectively forgotten again either. Archiving or
 deleting an item removes it from the strip immediately with no replacement
-until the next refresh — no whack-a-mole.
+until the next refresh, avoiding whack-a-mole.
 
 "Old enough to matter" uses the same period as the reminder setting above
 when reminders are on, or a 14-day default when they're off. It's fine (and
 expected) for the same item to show up both pinned/highlighted in the main
-shelf *and* in this strip at once — they're not trying to be non-overlapping,
+shelf *and* in this strip at once. They're not trying to be non-overlapping,
 just two different nudges.
 
-## Install — Chrome / Edge (unpacked)
+## Install on Chrome / Edge (unpacked)
 
 1. Go to `chrome://extensions` (or `edge://extensions`).
 2. Turn on **Developer mode** (top right).
 3. Click **Load unpacked** and select this folder.
-4. Open a new tab — you should see the Read it later page.
+4. Open a new tab. You should see the Read it later page.
 
-## Install — Firefox (temporary, for testing)
+## Install on Firefox (temporary, for testing)
 
 1. Go to `about:debugging#/runtime/this-firefox`.
 2. Click **Load Temporary Add-on…**
 3. Select the `manifest.json` file inside this folder.
 4. Open a new tab. Firefox will ask permission to let the extension
-   override the new tab page the first time — allow it.
+   override the new tab page the first time. Allow it.
 
 > Temporary add-ons in Firefox are removed when you close the browser.
 > For a permanent install, the extension needs to be signed by Mozilla
@@ -87,22 +99,22 @@ just two different nudges.
 
 Read it later keeps full items (including screenshot thumbnails) in
 `chrome.storage.local`, and also mirrors a lightweight copy of each item
-(url, title, domain, favicon, dates, archived state, spotlight backoff
-counters — no images) to
+(url, title, domain, favicon, dates, archived state, tags, spotlight
+backoff counters, never images) to
 `chrome.storage.sync`, one entry per item so each stays well under the
 8KB-per-item sync limit. On another device signed into the same browser
 account, opening the shelf pulls those in automatically; thumbnails just
 aren't part of what syncs, so items saved elsewhere show a favicon instead
 until re-saved on that device. Archiving and deleting also sync. This is
-all best-effort — offline, not signed in, or over the (~100KB / 512-item)
+all best-effort: offline, not signed in, or over the (~100KB / 512-item)
 sync quota just means that device keeps working from local storage alone.
 
 Note: `chrome.storage.sync` needs a stable extension ID to work, which
-only applies to a permanently installed, signed add-on — not a Firefox
+only applies to a permanently installed, signed add-on, not a Firefox
 "temporary add-on" loaded via `about:debugging` (see install notes above),
 which won't persist sync identity across restarts.
 
 ## Notes / things you might want to change
 
-- Icons in `icons/` are placeholders — swap them for your own artwork
+- Icons in `icons/` are placeholders. Swap them for your own artwork
   any time; sizes 16/32/48/128 are already wired up in `manifest.json`.