fix(faucet): repoint at api.ligate.io/v1/drip + cut v0.1.3 (closes #34)

[proofmancer]

Summary

• Fix ligate faucet broken: default URL dead, --faucet-url can't reach api.ligate.io/v1/drip #34: ligate faucet was broken in v0.1.2-devnet. The hardcoded default https://faucet.ligate.io no longer resolves (standalone ligate-io/faucet repo was archived; drip moved into ligate-api as POST /v1/drip), and the URL builder hardcoded a /faucet suffix so --faucet-url couldn't paper over the host change. Repoints DEFAULT_FAUCET_URL at https://api.ligate.io/v1/drip and drops the suffix so the configured URL is POSTed directly.
• Cuts v0.1.3 — first release on the project-wide clean-semver convention (no -devnet suffix). Matches ligate-chain v0.1.2, ligate-js, and ligate-api. Network identity stays in chain_id (ligate-devnet-1) and genesis dir names, not in the binary tag.
• Refreshes README.md faucet examples and "Related" link; drops the stale ligate-faucet repo pattern reference.

Response shape ({address, tx_hash, amount_nano, drip_amount_lgt}) is unchanged.

Test plan

Verified against live ligate-devnet-1 with a release-build binary:

• ligate --version reports ligate 0.1.3
• ligate faucet --help shows default https://api.ligate.io/v1/drip
• Real drip: ligate faucet lig1wlathcrhl93kmpkyu96xe33ceqqy7qdhk54ku7lazgvs5l834a0 → Drip accepted by faucet: 100 $LGT, tx: ltx12ngwqvg9url8hws9xxqvd59hqlg4m0m9raxuaa8wdva4c4478z0qh6e057. GET /v1/drip/status addresses_dripped incremented 0 → 1.
• Error path: invalid address returns clean faucet returned 400 Bad Request: ... invalid string length via FaucetError deserializer.
• --faucet-url override: works with and without trailing slash (trim_end_matches('/')).
• Broken baseline: stale v0.1.1-devnet binary reproduces both failure modes from ligate faucet broken: default URL dead, --faucet-url can't reach api.ligate.io/v1/drip #34 (DNS on faucet.ligate.io, 404 on suffix-doubling).
• cargo fmt --check clean (also enforced by pre-commit hook on this commit).

Release: tag v0.1.3 once merged; the cross-platform release workflow at .github/workflows/release.yml does the rest.