Fix compatibility with current nostr-tools

[bitcoin3us]

Problem

vite build fails against recent nostr-tools releases:

RollupError: "replaceAll" is not exported by "node_modules/nostr-tools/lib/esm/nip27.js", imported by "src/util/ui.ts".

nostr-tools removed the matchAll / replaceAll helpers from its nip27 module — current versions export only parse. A few AbstractRelay APIs that network.ts relied on have also changed. Since package.json declares nostr-tools: ^2.7.1 (which resolves to the latest 2.x), a clean npm install + vite build currently aborts.

Changes

nip27 — vendor a minimal src/util/nip27.ts that restores exactly the matchAll / replaceAll behaviour ZapThreads used: it matches NIP-21 nostr: references and decodes them via nip19. ui.ts imports from the local module instead of nostr-tools/nip27; behaviour is unchanged (decode failures are skipped / passed through rather than thrown).

network.ts — port to the current AbstractRelay API:

• connectionTimeout is no longer a settable property — the timeout is passed per call via relay.connect({ timeout }).
• The private _onauth hook was removed. It is dropped here; relays that require NIP-42 AUTH to read are already detected from the subscription close reason in handleClose, so behaviour is preserved.
• PrioritizedPool's constructor is typed with AbstractRelayConstructorOptions (it only reads verifyEvent / websocketImplementation); AbstractPoolConstructorOptions now requires fields the class does not use.
• window.nostr.getRelays() is now optional in the Nostr type — guarded.

Testing

• Builds cleanly against nostr-tools 2.23.x — vite build produces dist/ with no errors related to these changes.
• Verified in a browser on a live NIP-52 calendar event: relay connections, comment loading, and the comment composer all work.
• Two pre-existing, unrelated TS warnings remain (index.tsx Section typing, remarkable/linkify missing types) — left out of scope.

Note

package.json still declares nostr-tools: ^2.7.1, but the code now targets the current relay API — you may want to bump that range. Left unchanged to keep this PR focused.