feat(ci): automate Linux release builds and Gitea releases

Local flow is now ./release 1.6.7 (or make release VERSION=1.6.7):
bump wails.json productVersion, commit the bump, generate git-cliff
notes into an annotated plain-version tag, and push commit plus tag.
The tag push fires the new Gitea Actions workflow.

- cliff.toml: git-cliff groups matching Bookhoard, tag_pattern for
  plain versions so --latest scopes correctly.
- Makefile release target: strict plain-semver validation, dirty-tree
  and existing-tag guards, python3 wails.json bump committed as
  chore(release), throwaway-tag notes generation, push of main + tag.
- release: wrapper normalizing v/AniTrack- prefixes to plain versions.
- .gitea/workflows/release.yml: version guard (wails.json vs tag,
  base-match for -suffix pre-releases), Go 1.25 / Node 20 / Wails
  v2.15.0 + webkit2_41 system deps, environment.go from Actions
  secrets, make build, AniTrack-<version>.tar.gz packaged from
  build/ (bin, icon, desktop, install script, README), idempotent
  Release create/update named AniTrack-<version> with archive
  attached via REGISTRY_TOKEN PAT.

cliff.toml

@@ -0,0 +1,37 @@
+# git-cliff configuration — generates the body of each Gitea Release from
+# Conventional Commits accumulated since the previous tag. Invoked locally by
+# `make release VERSION=...`; the annotated tag message becomes the Release
+# body in .gitea/workflows/release.yml. Tags are plain versions (1.6.7).
+# Docs: https://git-cliff.org/docs/configuration
+
+[changelog]
+header = ""
+body = """
+{% for group, commits in commits | group_by(attribute="group") %}\
+### {{ group | upper_first }}
+{% for commit in commits %}\
+- {% if commit.scope %}*({{ commit.scope }})* {% endif %}{{ commit.message | upper_first }} ({{ commit.id | truncate(length=7, end="") }})
+{% endfor %}\
+{% endfor %}\
+"""
+trim = true
+footer = ""
+
+[git]
+conventional_commits = true
+filter_unconventional = false
+require_conventional = false
+split_commits = false
+commit_parsers = [
+  { message = "^feat", group = "Features" },
+  { message = "^fix", group = "Bug Fixes" },
+  { message = "^perf", group = "Performance" },
+  { message = "^refactor", group = "Refactor" },
+  { message = "^docs", group = "Documentation" },
+  { message = "^test", group = "Tests" },
+  { message = "^chore|^ci", group = "Miscellaneous Tasks" },
+  { message = ".*", group = "Other" },
+]
+filter_commits = false
+tag_pattern = "[0-9].*"
+sort_commits = "oldest"