Current templates: safe.directory, golangci-lint v2.14.0, fetch-depth 0, the policy's last stage (closes #50)

REPO_POLICIES.md and .golangci.yml are the sneak/prompts next copies, and
.dockerignore takes the template's .git/modules/**/config line. The lint
phase runs golangci-lint v2.14.0; its two errors.AsType findings are
fixed. The stage that builds keyfunc marks /src safe for git, so a
context sent as a tar stream still yields a version. That stage is now
the last one and a development environment on the Debian Go image: what
script/bootstrap installs, the source in /src, keyfunc on the PATH. The
test phase uses the same image, so one Go image stays matched to
script/bootstrap. The CI checkout fetches all history and tags.

Model: opus-5-5

.golangci.yml

@@ -17,6 +17,7 @@ linters:
   disable:
     # Genuinely incompatible with project patterns
     - exhaustruct      # Requires all struct fields
+    - exhaustruct_v5   # Requires all struct fields (successor to exhaustruct)
     - godot            # Requires comments to end with periods
     - wrapcheck        # Too verbose for internal packages
     - varnamelen       # Short names like db, id are idiomatic Go