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.ps1

@@ -0,0 +1,111 @@
+# issue-assign.ps1 - Assign issues on Gitea or GitHub
+# Usage: .\issue-assign.ps1 -Issue ISSUE_NUMBER [-Assignee assignee] [-Labels labels] [-Milestone milestone]
+
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory=$true)]
+    [Alias("i")]
+    [int]$Issue,
+
+    [Alias("a")]
+    [string]$Assignee,
+
+    [Alias("l")]
+    [string]$Labels,
+
+    [Alias("m")]
+    [string]$Milestone,
+
+    [Alias("r")]
+    [switch]$RemoveAssignee,
+
+    [Alias("h")]
+    [switch]$Help
+)
+
+$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+. "$ScriptDir\detect-platform.ps1"
+
+function Show-Usage {
+    @"
+Usage: issue-assign.ps1 [OPTIONS]
+
+Assign or update an issue on the current repository (Gitea or GitHub).
+
+Options:
+    -Issue, -i NUMBER       Issue number (required)
+    -Assignee, -a USER      Assign to user (use @me for self)
+    -Labels, -l LABELS      Add comma-separated labels
+    -Milestone, -m NAME     Set milestone
+    -RemoveAssignee, -r     Remove current assignee
+    -Help, -h               Show this help message
+
+Examples:
+    .\issue-assign.ps1 -i 42 -a "username"
+    .\issue-assign.ps1 -i 42 -l "in-progress" -m "0.2.0"
+    .\issue-assign.ps1 -i 42 -a @me
+"@
+    exit 1
+}
+
+if ($Help) {
+    Show-Usage
+}
+
+$platform = Get-GitPlatform
+
+switch ($platform) {
+    "github" {
+        if ($Assignee) {
+            gh issue edit $Issue --add-assignee $Assignee
+        }
+        if ($RemoveAssignee) {
+            $current = gh issue view $Issue --json assignees -q '.assignees[].login' 2>$null
+            if ($current) {
+                $assignees = ($current -split "`n") -join ","
+                gh issue edit $Issue --remove-assignee $assignees
+            }
+        }
+        if ($Labels) {
+            gh issue edit $Issue --add-label $Labels
+        }
+        if ($Milestone) {
+            gh issue edit $Issue --milestone $Milestone
+        }
+        Write-Host "Issue #$Issue updated successfully"
+    }
+    "gitea" {
+        $needsEdit = $false
+        $cmd = @("tea", "issue", "edit", $Issue)
+
+        if ($Assignee) {
+            $cmd += @("--assignees", $Assignee)
+            $needsEdit = $true
+        }
+        if ($Labels) {
+            $cmd += @("--labels", $Labels)
+            $needsEdit = $true
+        }
+        if ($Milestone) {
+            $milestoneList = tea milestones list 2>$null
+            $milestoneId = ($milestoneList | Select-String "^\s*(\d+).*$Milestone" | ForEach-Object { $_.Matches.Groups[1].Value } | Select-Object -First 1)
+            if ($milestoneId) {
+                $cmd += @("--milestone", $milestoneId)
+                $needsEdit = $true
+            } else {
+                Write-Warning "Could not find milestone '$Milestone'"
+            }
+        }
+
+        if ($needsEdit) {
+            & $cmd[0] $cmd[1..($cmd.Length-1)]
+            Write-Host "Issue #$Issue updated successfully"
+        } else {
+            Write-Host "No changes specified"
+        }
+    }
+    default {
+        Write-Error "Could not detect git platform"
+        exit 1
+    }
+}