Fix review issues: front matter, headings, consistency, typos

- Move title and last_modified to YAML front matter (all policy docs)
- Make all document sections H1, subsections H2
- Update version rule to reference front matter format
- Fix "our" → "your" typo in Go styleguide
- Fix Python styleguide numbering (2. → 1.)
- Fix README: "flat collection" → accurate description, remove stale TODO
- Remove Makefile items from code styleguides (repo stuff, not code),
  add note linking to Repository Policies
- Change zerolog → slog in Go styleguide
- Fix JS styleguide npm reference: both work, but use make targets
- Drop .json from healthcheck path, add JSON content-type requirement
- Add Author/License to Go HTTP Server Conventions
- Convert hyperlinks to backtick URLs in checklists for consistency
- Add version/front matter to both checklists

prompts/CODE_STYLEGUIDE_GO.md

@@ -1,6 +1,7 @@
-Version: 2026-02-22
-
-# Golang
+---
+title: Code Styleguide — Go
+last_modified: 2026-02-22
+---
 
 1.  Try to hard wrap long lines at 77 characters or less.
 
@@ -70,11 +71,8 @@ Version: 2026-02-22
 1.  Avoid obvious footguns. For example, use range instead of for loops for
     iterating.
 
-1.  Try to use zerolog for logging. It's fast and has a nice API. For
-    smaller/quick projects, the standard library's `log` package (and
-    specifically `log/slog`) is fine. In that case, log structured logs whenever
-    possible, and import `sneak.berlin/go/simplelog` to configure it
-    appropriately. Example:
+1.  Use `log/slog` for structured logging. Import `sneak.berlin/go/simplelog`
+    for sensible defaults. Example:
 
     ```go
     package main
@@ -107,9 +105,9 @@ Version: 2026-02-22
     able-to-be-compiled state, linted, and any tests run. The Docker build
     should fail if linting doesn't pass.
 
-1.  Include a `Makefile` with targets for at least `clean` and `test`. If there
-    are multiple binaries, include a target for each binary. If there are
-    multiple binaries, include a target for `all` that builds all binaries.
+1.  Every repo must have a `Makefile`. See
+    [Repository Policies](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/REPO_POLICIES.md)
+    for required targets and conventions.
 
 1.  If you are writing a single-module library, `.go` files are okay in the repo
     root.
@@ -132,7 +130,7 @@ Version: 2026-02-22
     single-file scripts.
 
 1.  HTTP HandleFuncs should be returned from methods or functions that need to
-    handle HTTP requests. Don't use methods or our top level functions as
+    handle HTTP requests. Don't use methods or your top level functions as
     handlers.
 
 1.  Provide a .gitignore file that ignores at least `*.log`, `*.out`, and
@@ -431,7 +429,7 @@ Version: 2026-02-22
     releasable". "Releasable" in this context means that it builds and functions
     as expected, and that all tests and linting passes.
 
-## Other Golang Tips and Best Practices (Optional)
+# Other Golang Tips and Best Practices (Optional)
 
 1. For any internet-facing http server, set appropriate timeouts and limits to
    protect against slowloris attacks or huge uploads that can consume server