v0.1: Grav-only repo + CI lint + branch-preview architecture

Pipeline fully retired: src/, contract-inputs/, service-csv/ deleted;
their content is fully superseded by grav/user/pages (verified section
by section). New: gitea actions lint workflow (markdownlint + typos
blocking, vale prose + lychee links advisory), lint configs, README
documents the branch/PR model, docs/branch-previews.md is the LAMP +
wildcard + Git Sync runbook for <branch>.contract.knownelement.com.
Blocking checks verified green before push (pinned containers).

Ticket: https://projects.knownelement.com/issues/924

.typos.toml

@@ -0,0 +1,6 @@
+# Spell-check config (crate-ci/typos). Blocking in CI.
+# Add deliberate non-word strings here as needed, e.g.:
+# [default.extend-identifiers]
+[default.extend-words]
+KNEL = "KNEL"
+kneldc = "kneldc"