fix(context): sync to the estate canonical context-sync.sh, drop Cursor/Aider

Same drift as gitea-mcp: this repo's copy of context-sync.sh was two days
stale against dma-cli's canonical (Mathias's Cursor/Aider decision,
2026-09-01) and CLAUDE.md itself was stale enough to need 97 lines of
correction on regeneration -- this repo's context:sync was apparently never
wired into `task check` at all (no drift assertion existed in its Taskfile),
so nothing had been catching it.

Found while building the estate-wide context-sync drift gate (ADR-0019).

- script synced to canonical hash
- .cursorrules, .aider.conventions.md, .aider.conf.yml deleted
- stale context:sync:cursor Taskfile shortcut removed (would now hit the
  canonical script's own `exit 1` on an unknown adapter name)
- CLAUDE.md, AGENTS.md, .context/system-prompt.txt regenerated against canonical

task check -> exit 0.

scripts/context-sync.sh

@@ -5,6 +5,11 @@
 # For Claude Code: generates project-only CLAUDE.md (it inherits root via tree walk)
 # For everything else: concatenates root AGENT.md + project PROJECT.md
 #
+# Cursor and Aider adapters removed 2026-09-01 — neither is a supported harness
+# any more. Supported: Claude Code, Antigravity, OpenCode, Mistral Vibe, Crush,
+# Pi. All read CLAUDE.md or AGENTS.md; system-prompt.txt remains for Open WebUI,
+# Mods and raw API use.
+#
 # Usage: ./scripts/context-sync.sh [--force] [adapter...]
 # Task:  task context:sync
 #
@@ -95,30 +100,6 @@ generate_agents() {
   echo "  → AGENTS.md (root + project; Crush, Pi, Antigravity)"
 }
 
-# ── Cursor ───────────────────────────────────────────────────
-generate_cursor() {
-  {
-    echo "# Cursor rules — auto-generated"
-    echo "# Do not edit. Run: task context:sync"
-    echo ""
-    root_block
-    cat "$PROJECT_FILE"
-  } > .cursorrules
-  echo "  → .cursorrules (root + project)"
-}
-
-# ── Aider ────────────────────────────────────────────────────
-generate_aider() {
-  { root_block; cat "$PROJECT_FILE"; } > .aider.conventions.md
-  if [ ! -f .aider.conf.yml ]; then
-    cat > .aider.conf.yml << 'YAML'
-read: .aider.conventions.md
-auto-commits: false
-YAML
-  fi
-  echo "  → .aider.conventions.md (root + project)"
-}
-
 # ── Generic system prompt (Open WebUI, Mods, etc.) ──────────
 generate_system_prompt() {
   {
@@ -180,8 +161,6 @@ echo "Syncing project context from $PROJECT_FILE..."
 if [ ${#ADAPTERS[@]} -eq 0 ]; then
   generate_claude
   generate_agents
-  generate_cursor
-  generate_aider
   generate_system_prompt
   generate_mcp
 else
@@ -189,8 +168,6 @@ else
     case "$adapter" in
       claude)  generate_claude ;;
       agents)  generate_agents ;;
-      cursor)  generate_cursor ;;
-      aider)   generate_aider ;;
       prompt|system|openwebui|owui|generic) generate_system_prompt ;;
       mcp)     generate_mcp ;;
       *) echo "Unknown adapter: $adapter" >&2; exit 1 ;;