chore: planning gate — milestones, issues, and task breakdown

Break PRD into 8 milestones (Phase 0–7) with 59 issues on Gitea.
Populate TASKS.md, update mission manifest, initialize scratchpad.
Repo created at git.mosaicstack.dev/mosaic/mosaic-stack.

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

scripts/agent/session-end.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+source "$SCRIPT_DIR/common.sh"
+
+ensure_repo_root
+load_repo_hooks
+
+# ─── Mission session cleanup (ORCHESTRATOR-PROTOCOL) ────────────────────────
+ORCH_DIR=".mosaic/orchestrator"
+MISSION_JSON="$ORCH_DIR/mission.json"
+SESSION_LOCK="$ORCH_DIR/session.lock"
+COORD_LIB="$HOME/.config/mosaic/tools/orchestrator/_lib.sh"
+
+if [[ -f "$SESSION_LOCK" ]] && [[ -f "$COORD_LIB" ]] && command -v jq &>/dev/null; then
+  # shellcheck source=/dev/null
+  source "$COORD_LIB"
+
+  sess_id="$(jq -r '.session_id // ""' "$SESSION_LOCK")"
+  if [[ -n "$sess_id" && -f "$MISSION_JSON" ]]; then
+    # Update mission.json: mark session ended
+    updated="$(jq \
+      --arg sid "$sess_id" \
+      --arg ts "$(iso_now)" \
+      --arg reason "completed" \
+      '(.sessions[] | select(.session_id == $sid)) |= . + {
+        ended_at: $ts,
+        ended_reason: $reason
+      }' "$MISSION_JSON")"
+    echo "$updated" > "$MISSION_JSON.tmp" && mv "$MISSION_JSON.tmp" "$MISSION_JSON"
+    echo "[agent-framework] Session $sess_id recorded in mission state"
+  fi
+
+  session_lock_clear "."
+fi
+
+if declare -F mosaic_hook_session_end >/dev/null 2>&1; then
+  run_step "Run repo end hook" mosaic_hook_session_end
+else
+  echo "[agent-framework] No repo end hook configured (.mosaic/repo-hooks.sh)"
+fi
+
+if git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+  run_step "Show status" git status --short
+  run_step "Show diff summary" git diff --stat
+fi