docs: lift user-facing guides to recipes/, drop dangling docs/ refs

docs/ is gitignored; references to docs/implementation/*.md from public
source, configs, and packaging were dead links outside the maintainer
machine. Adds four recipes (README, dnsdist-front, doh-on-lan,
odoh-upstream) under top-level recipes/ and repoints existing pointers.

- numa.toml, packaging/client/{README.md,numa.toml}: point to
  recipes/odoh-upstream.md.
- src/{bootstrap_resolver,forward,serve}.rs: reference issue #122
  directly (module scope is broader than the ODoH-specific recipe).
- src/health.rs: drop the §-ref; iOS HealthInfo remains named as the
  canonical consumer.

src/bootstrap_resolver.rs

@@ -2,8 +2,7 @@
 //! relay/target, blocklist CDN). When numa is its own system resolver
 //! (`/etc/resolv.conf → 127.0.0.1`, HAOS add-on, Pi-hole-style container),
 //! the default `getaddrinfo` path loops back through numa before numa can
-//! answer — a chicken-and-egg that deadlocks cold boot. See issue #122 and
-//! `docs/implementation/bootstrap-resolver.md`.
+//! answer — a chicken-and-egg that deadlocks cold boot. See issue #122.
 //!
 //! Resolution order per hostname:
 //! 1. Per-hostname overrides (e.g. ODoH `relay_ip` / `target_ip`) → return

src/forward.rs

@@ -175,8 +175,7 @@ pub fn parse_upstream(
 ///
 /// Uses the system resolver. Callers running inside `serve::run` pass the
 /// shared [`crate::bootstrap_resolver::NumaResolver`] via
-/// [`build_https_client_with_resolver`] to avoid the self-loop documented
-/// in `docs/implementation/bootstrap-resolver.md`.
+/// [`build_https_client_with_resolver`] to avoid the self-loop (issue #122).
 pub fn build_https_client() -> reqwest::Client {
     build_https_client_with_resolver(1, None)
 }

src/health.rs

@@ -7,11 +7,10 @@
 //! Both handlers call [`HealthResponse::build`] to assemble the JSON
 //! response from `HealthMeta` + live inputs.
 //!
-//! JSON schema is documented in `docs/implementation/ios-companion-app.md`
-//! §4.2. The iOS companion app's `HealthInfo` struct is the canonical
-//! consumer; any change to this response must keep that struct decoding
-//! cleanly (all consumed fields are optional on the Swift side, but
-//! `lan_ip` is load-bearing for the pipeline).
+//! The iOS companion app's `HealthInfo` struct is the canonical consumer;
+//! any change to this response must keep that struct decoding cleanly (all
+//! consumed fields are optional on the Swift side, but `lan_ip` is
+//! load-bearing for the pipeline).
 
 use std::net::Ipv4Addr;
 use std::path::Path;

src/serve.rs

@@ -52,7 +52,6 @@ pub async fn run(config_path: String) -> crate::Result<()> {
     // Routes numa-originated HTTPS (DoH upstream, ODoH relay/target, blocklist
     // CDN) away from the system resolver so lookups don't loop back through
     // numa when it's its own system DNS.
-    // See `docs/implementation/bootstrap-resolver.md`.
     let resolver_overrides = match config.upstream.mode {
         crate::config::UpstreamMode::Odoh => config
             .upstream