feat: add the party id input component

[gabitoesmiapodo]

Closes #8

Note: this merges into #74 so review that one first.

Summary

A dApp had no way to let a user enter a Canton party id, so every form rolled its own shape check.

Changes

• Controlled PartyIdInput reports every change and its validation error to the caller
• A malformed value is flagged with aria-invalid from the first blur onward, never while first typing
• Pasted whitespace is trimmed on blur
• validatePartyId and isValidPartyId are exported so a form can gate submit on the same check
• The grant form's receiver field uses the new input and supplies its own error wording
• Demo seed party ids now carry full 68-character fingerprints

Deviations

Against the issue's requirements

• A valid value stays as typed; truncating inside an editable field would fight the caret, so <Identifier> still owns formatted display
• No TextInput primitive exists in the kit, so the field renders a plain <input>; the issue's note assumed one that was never built

Rode along with the work

• Dropped the unused ref prop from Identifier and ExplorerLink, never consumed by anyone
• Added scripts/add-component.mjs, a component scaffolder written while making this one
• The explorer link now requires a well-formed party id, so the package holds one definition of the shape instead of two

Acceptance criteria

• Controlled component: value in via prop, changes reported via callback
• Flags input that doesn't match the basic party id shape
• Displays a valid value in truncated/formatted form
• Built on the existing text input primitive, not a new input from scratch

Test plan

Automated tests

1. Run pnpm install from the repo root
2. Run pnpm -C canton-dappbooster test
3. Expect 103 passing tests across 9 files
4. Run pnpm lint and pnpm typecheck from the root and expect no errors

Manual verification

1. Check out this branch and run pnpm run app:dev
2. Open http://localhost:3012, pick a party, and go to the create-grant page
3. Type nico into Receiver party id, then click elsewhere
4. Expect a red field and "Use a full party id (hint::fingerprint)."
5. Paste a full hint::fingerprint id with a leading space, then click elsewhere
6. Expect the space gone, the red state cleared, and Create enabled

Breaking changes

Identifier and ExplorerLink no longer accept a ref prop.
Nothing in this repo passed one; a consumer that does should drop it or request it back.

Checklist

• Self-reviewed my own diff
• Tests added or updated
• Docs updated (if applicable)
• No unrelated changes bundled in

Screenshots