Restore Desktop shortcuts and start tax reporting core

[sridharkalaibala]

Changes

Restores the green Desktop shortcut and desktop tool menu, including direct Kitchen Display and Kitchen sound actions. Table names now use normal text alignment in both add and edit forms.

Adds the first internal Tax & Compliance calculation boundary: exact decimal totals, timezone-aware periods, signed adjustments, duplicate/scope checks and explicit incomplete-source states. It is not yet connected to routes, screens or exports and must not be described as a usable tax report. The implementation status and remaining work are documented in docs/TAX_REPORTING_CORE.md.

Validation

• 51 focused tax/GSTR tests passed.
• 22 desktop menu/settings tests passed.
• Frontend asset build passed.
• Repository local checks run before push.

Sync and rollout

No business-data writes, schema changes or new sync collections. Existing sales, receivings, expenses and branches lanes were inspected across POS, Gateway and agent definitions. No live-device sync or accountant reconciliation is claimed. Merge through develop, then main; installed desktop clients need an updated build for the UI fixes.

[github-actions]

Merged to develop. Anyone can test this - you do not need write access.

Try it at https://develop.posnic.io, or run it yourself:

git fetch origin develop && git checkout develop
npm install && npm --prefix api install
npm run dev   # then http://localhost:3000

When you have tested it, say what you did and what happened, and set
QA passed or QA failed. If you cannot set labels, just comment -
a maintainer will.

Reporting that something is broken is as useful as fixing it. It is
better found here than by a shopkeeper.