fix: accept any d-tag identifier; percent-encode in URLs

NIP-01 places no restriction on d tag characters and NIP-34 only
recommends kebab-case without mandating it. Rejecting identifiers with
whitespace or other URL-unsafe characters was therefore overly strict.

The correct approach (per NIP-34 PR #2312 and GRASP-01) is to store
identifiers verbatim on disk and percent-encode them when constructing
URLs. The previous commit already handled the incoming direction
(percent-decoding URL paths before filesystem lookup); this commit
handles the outgoing direction and removes the validation restriction.

Changes:
- validate_identifier: drop whitespace rejection; only reject chars
  that are unsafe as filesystem directory names (/, \, null, . / ..)
- git/mod.rs: add percent_encode() alongside percent_decode()
- landing.rs: percent-encode identifier in nostr:// clone URL and
  gitworkshop link (also fixes a pre-existing bug where the clone URL
  displayed literal '{npub}' / '{identifier}' instead of the values)

1 files changed, 4 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 217781c..633ddbf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Repository identifiers containing characters that require percent-encoding in URLs (e.g. spaces, emoji) are now accepted and served correctly. NIP-01 places no restriction on `d` tag values and NIP-34 only recommends kebab-case without mandating it, so rejecting non-kebab identifiers was overly strict. Identifiers are stored verbatim on disk and percent-encoded when used in URLs, per the `nostr://` clone URL spec formalised in [NIP-34 PR #2312](https://github.com/nostr-protocol/nips/pull/2312) and the GRASP-01 HTTP path spec. The landing page clone URL now also correctly percent-encodes the identifier.
+
 ### Changed
 
 - Remove arbitrary default max connections limit; when `NGIT_MAX_CONNECTIONS` is unset the relay imposes no connection cap, deferring to OS fd limits and infrastructure controls