fix(api): normalize trailing slashes — no slash on param routes

Rule: trailing slash only on collection roots (/). Any route containing
a path parameter {…} uses no trailing slash. Applies across all routers,
scripts, Makefile, and tests. Fixes 307-redirect fragility on POST/PATCH
from naive clients (curl, Codex HTTP calls).

Also adds POST /repos/{slug}/sync — runs ADR-001 consistency check with
--fix via HTTP, so non-MCP agents (Codex) can self-service DB sync without
operator intervention.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/install_hooks.sh

@@ -45,7 +45,7 @@ resolve_path() {
   local slug="$1"
   # Try the registered local_path first
   local api_path
-  api_path=$(curl -sf "${API_BASE}/repos/${slug}/" | python3 -c \
+  api_path=$(curl -sf "${API_BASE}/repos/${slug}" | python3 -c \
     "import json,sys; d=json.load(sys.stdin); print(d.get('local_path') or '')" 2>/dev/null || true)
   if [[ -n "$api_path" && -d "$api_path" ]]; then
     echo "$api_path"