feat: integrate framework files into monorepo under packages/mosaic/framework/

Moves all Mosaic framework runtime files from the separate bootstrap repo
into the monorepo as canonical source. The @mosaic/mosaic npm package now
ships the complete framework — bin scripts, runtime configs, tools, and
templates — enabling standalone installation via npm install.

Structure:
  packages/mosaic/framework/
  ├── bin/          28 CLI scripts (mosaic, mosaic-doctor, mosaic-sync-skills, etc.)
  ├── runtime/      Runtime adapters (claude, codex, opencode, pi, mcp)
  ├── tools/        Shell tooling (git, prdy, orchestrator, quality, etc.)
  ├── templates/    Agent and repo templates
  ├── defaults/     Default identity files (AGENTS.md, STANDARDS.md, SOUL.md, etc.)
  ├── install.sh    Legacy bash installer
  └── remote-install.sh  One-liner remote installer

Key files with Pi support and recent fixes:
- bin/mosaic: launch_pi() with skills-local loop
- bin/mosaic-doctor: --fix auto-wiring for all 4 harnesses
- bin/mosaic-sync-skills: Pi as 4th link target, symlink-aware find
- bin/mosaic-link-runtime-assets: Pi settings.json patching
- bin/mosaic-migrate-local-skills: Pi skill roots, symlink find
- runtime/pi/RUNTIME.md + mosaic-extension.ts

Package ships 251 framework files in the npm tarball (278KB compressed).

packages/mosaic/framework/tools/git/issue-assign.sh

@@ -0,0 +1,135 @@
+#!/bin/bash
+# issue-assign.sh - Assign issues on Gitea or GitHub
+# Usage: issue-assign.sh -i ISSUE_NUMBER [-a assignee] [-l labels] [-m milestone]
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/detect-platform.sh"
+
+# Default values
+ISSUE=""
+ASSIGNEE=""
+LABELS=""
+MILESTONE=""
+REMOVE_ASSIGNEE=false
+
+usage() {
+    cat <<EOF
+Usage: $(basename "$0") [OPTIONS]
+
+Assign or update an issue on the current repository (Gitea or GitHub).
+
+Options:
+    -i, --issue NUMBER      Issue number (required)
+    -a, --assignee USER     Assign to user (use @me for self)
+    -l, --labels LABELS     Add comma-separated labels
+    -m, --milestone NAME    Set milestone
+    -r, --remove-assignee   Remove current assignee
+    -h, --help              Show this help message
+
+Examples:
+    $(basename "$0") -i 42 -a "username"
+    $(basename "$0") -i 42 -l "in-progress" -m "0.2.0"
+    $(basename "$0") -i 42 -a @me
+EOF
+    exit 1
+}
+
+# Parse arguments
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        -i|--issue)
+            ISSUE="$2"
+            shift 2
+            ;;
+        -a|--assignee)
+            ASSIGNEE="$2"
+            shift 2
+            ;;
+        -l|--labels)
+            LABELS="$2"
+            shift 2
+            ;;
+        -m|--milestone)
+            MILESTONE="$2"
+            shift 2
+            ;;
+        -r|--remove-assignee)
+            REMOVE_ASSIGNEE=true
+            shift
+            ;;
+        -h|--help)
+            usage
+            ;;
+        *)
+            echo "Unknown option: $1" >&2
+            usage
+            ;;
+    esac
+done
+
+if [[ -z "$ISSUE" ]]; then
+    echo "Error: Issue number is required (-i)" >&2
+    usage
+fi
+
+PLATFORM=$(detect_platform)
+
+case "$PLATFORM" in
+    github)
+        if [[ -n "$ASSIGNEE" ]]; then
+            gh issue edit "$ISSUE" --add-assignee "$ASSIGNEE"
+        fi
+        if [[ "$REMOVE_ASSIGNEE" == true ]]; then
+            # Get current assignees and remove them
+            CURRENT=$(gh issue view "$ISSUE" --json assignees -q '.assignees[].login' 2>/dev/null | tr '\n' ',')
+            if [[ -n "$CURRENT" ]]; then
+                gh issue edit "$ISSUE" --remove-assignee "${CURRENT%,}"
+            fi
+        fi
+        if [[ -n "$LABELS" ]]; then
+            gh issue edit "$ISSUE" --add-label "$LABELS"
+        fi
+        if [[ -n "$MILESTONE" ]]; then
+            gh issue edit "$ISSUE" --milestone "$MILESTONE"
+        fi
+        echo "Issue #$ISSUE updated successfully"
+        ;;
+    gitea)
+        # tea issue edit syntax
+        CMD="tea issue edit $ISSUE"
+        NEEDS_EDIT=false
+
+        if [[ -n "$ASSIGNEE" ]]; then
+            # tea uses --assignees flag
+            CMD="$CMD --assignees \"$ASSIGNEE\""
+            NEEDS_EDIT=true
+        fi
+        if [[ -n "$LABELS" ]]; then
+            # tea uses --labels flag (replaces existing)
+            CMD="$CMD --labels \"$LABELS\""
+            NEEDS_EDIT=true
+        fi
+        if [[ -n "$MILESTONE" ]]; then
+            MILESTONE_ID=$(tea milestones list 2>/dev/null | grep -E "^\s*[0-9]+" | grep "$MILESTONE" | awk '{print $1}' | head -1)
+            if [[ -n "$MILESTONE_ID" ]]; then
+                CMD="$CMD --milestone $MILESTONE_ID"
+                NEEDS_EDIT=true
+            else
+                echo "Warning: Could not find milestone '$MILESTONE'" >&2
+            fi
+        fi
+
+        if [[ "$NEEDS_EDIT" == true ]]; then
+            eval "$CMD"
+            echo "Issue #$ISSUE updated successfully"
+        else
+            echo "No changes specified"
+        fi
+        ;;
+    *)
+        echo "Error: Could not detect git platform" >&2
+        exit 1
+        ;;
+esac