feat(continue): resume reading and games on another device

[MadhuS-1605]

Summary

Start on one device, carry on with another — no account, no server. A "Continue on another device" trigger on the reader, Padabandha, the daily word, and Collections builds a single progress snapshot and shows a QR code + link. The whole snapshot rides inside the URL hash (base64url JSON, ~36h self-expiry); nothing is uploaded and the daily-word answer is never included. Consistent with the site's offline-first, serverless design.

Closes: #21

What changed

• blobCodec — encode/decode the progress blob for the URL hash, with version + expiry checks so an old or corrupt link fails cleanly. fitContinueUrl sheds optional parts (stars, then Padabandha) to keep the QR scannable, always keeping the reading position and the daily-word date/guesses.
• buildProgress / applyProgress — read and write the same localStorage keys each feature already uses (reader progress, Padabandha grid, daily-word guesses, Favourites collection). No second save format.
• loadWordGameState — replays a target-less carry-over record onto today's word instead of dropping it; normal local play is unaffected.
• QrCode — inline SVG QR (pure qrcode-generator encoder, no canvas/network) with the Sirigannada mark knocked into the centre; error correction forced to "H" so the logo never breaks the scan.
• /continue — landing page decodes the hash, applies progress into the features' own keys, then does a full-page redirect to the right screen (reading position wins, then games, then collections).
• Entry points — labelled button on Padabandha / daily word / Collections; icon in the reader top bar.
• Docs: README section (Kannada + English). .gitignore: ignore .claude-flow/. next.config.ts: removed stray dev-only cruft.

Testing

• npm run typecheck — clean
• npm test — 517 passing (66 files), including new blobCodec.test.ts and applyProgress.test.ts
• npm run build — succeeds; /continue prerenders as static content

[github-actions]

Preview (commit 0b357a5): https://preview-pr-75.sirigannada.pages.dev

Cloudflare needs a minute or two to build after each push. Test on a phone width. The branch preview/pr-75 is deleted automatically when this PR closes.

[MadhuS-1605]

Merged main into this branch and resolved the conflicts (merge commit 0b357a5, DCO signed).

Conflicting files: src/components/icons/index.tsx and src/lib/i18n.ts — both trivial append-only unions:

• icons/index.tsx — kept this branch's DevicesIcon alongside main's new BookOpenIcon/GamepadIcon/MenuIcon/ChevronDownIcon/PlayIcon/PauseIcon/SquareIcon.
• i18n.ts — kept ...continueStrings alongside main's ...homeStrings/...moreStrings/...searchStrings/...contactStrings (imports auto-merged cleanly).

npm run typecheck clean, npm test 579 passing. All CI checks green; PR now shows mergeable.