feat: split data update from site build; publish via Cloudflare Pages

The updater fetched GitHub metadata and rendered the dashboard payload in
a single step, so anything that published the site needed a GITHUB_TOKEN.
Cloudflare Pages builds from a Git webhook and has no business holding
one.

Split the tool into three modes. The default update step still fetches
GitHub and now records every API-sourced field in data/metadata.json,
which is committed alongside README.md and data/history.jsonl. The new
-build mode joins that snapshot with data/agents.yml and
data/history.jsonl to render dist/ with no network access and no token;
-check is unchanged.

Supporting changes:

- computeDeltaAt anchors the delta windows to when the data was fetched
  rather than the wall clock, so a redeploy days later reproduces the
  same Δ7d instead of sliding the window past its slack allowance.
- writeSiteData takes updatedAt explicitly for the same reason: the
  timestamp labels data freshness, not build time.
- sortStats is extracted from fetchStats so the build step re-ranks
  identically from committed metadata.
- An agents.yml entry with no metadata yet is omitted with a warning
  instead of failing the build, which would otherwise block every deploy
  between merging a new entry and the next nightly run.
- update.yml drops the GitHub Pages deploy steps and commits
  data/metadata.json; ci.yml runs `go run . -build` so a build that would
  break on deploy breaks in CI first.
- site/_headers stops the edge serving a stale data.json after a refresh.
- docs/DEPLOY.md covers the Cloudflare setup, including the one-time
  bootstrap of data/metadata.json that the build depends on.

Also carries the in-progress curation work already in the tree: the
module rename to awesome-ai-dev-tools, retagged entries, and removal of
the archived Roo-Code, void, continue and suna entries.

github.go

@@ -156,16 +156,21 @@ func fetchStats(token string, agents []Agent) ([]Stat, error) {
 		})
 	}
 
-	// Sort by stars descending. Ties are ordered by CanonicalKey for determinism
-	// regardless of map-iteration or agents.yml order.
+	sortStats(stats)
+
+	return stats, nil
+}
+
+// sortStats orders the ranking by stars descending. Ties break on CanonicalKey
+// for determinism regardless of map-iteration or agents.yml order. Shared with
+// the build step, which re-ranks from committed metadata.
+func sortStats(stats []Stat) {
 	sort.Slice(stats, func(i, j int) bool {
 		if stats[i].Stars != stats[j].Stars {
 			return stats[i].Stars > stats[j].Stars
 		}
 		return stats[i].CanonicalKey < stats[j].CanonicalKey
 	})
-
-	return stats, nil
 }
 
 // fetchChunk sends one GraphQL request for a slice of agents. aliasOffset
@@ -251,7 +256,7 @@ func doWithRetry(token string, body []byte) ([]byte, int, error) {
 		}
 		req.Header.Set("Authorization", "Bearer "+token)
 		req.Header.Set("Content-Type", "application/json")
-		req.Header.Set("User-Agent", "ai-dev-tools-updater")
+		req.Header.Set("User-Agent", "awesome-ai-dev-tools-updater")
 
 		resp, err := httpClient.Do(req)
 		if err != nil {