Seed bootapi templates + distro catalog

Initial content for bootapi's git-synced template set: the kickstart and iPXE
templates and the distro catalog (almalinux9, fedora) ported from bootapi's
embedded defaults, plus CI that validates every template/catalog renders for
every distro (bootapi validate) and shellchecks the %post blocks.

Claude-Session: https://claude.ai/code/session_015ur3i7D2azsMAWTSVABApv

.woodpecker/pre-commit.yaml

@@ -0,0 +1,18 @@
+when:
+  - event: [pull_request, push]
+
+steps:
+  - name: pre-commit
+    image: git.unkin.net/unkin/almalinux9-gobuilder:20260606
+    commands:
+      - uvx pre-commit run --all-files
+    backend_options:
+      kubernetes:
+        serviceAccountName: default
+        resources:
+          requests:
+            memory: 512Mi
+            cpu: 1
+          limits:
+            memory: 2Gi
+            cpu: 2