Add pr-dashboard skill and plugin (#1444)

* Add pr-dashboard skill and plugin

Adds a self-contained PR dashboard skill that generates and opens a
rich HTML dashboard in the browser showing GitHub pull requests for a
given date range and role filter.

- Skill: skills/pr-dashboard/ — bundles pr-dashboard-cli.mjs,
  dashboard.html, and lib/utils.mjs
- Plugin: plugins/pr-dashboard/ — makes it installable via
  `copilot skill install pr-dashboard@awesome-copilot`

Requires GitHub CLI (gh) installed and authenticated.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Restore README.instructions.md to upstream sort order

macOS locale sorts Japanese/Korean C# entries differently than Linux CI.
Restore to the upstream/staged version since we don't add any instructions.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address PR review comments

- Fix regex character class bug: [-to]+ → (?:-|to) alternation in utils.mjs
- Fix 'last week' to return previous calendar week (Mon–Sun) not last 7 days
- Remove unused formatHumanDate and buildMarkdown exports from utils.mjs
- Fix ghApi error handling: rethrow with helpful message instead of silently
  returning parsed JSON on failure (prevents silent auth errors)
- Add pagination to searchIssues (up to 1000 results across pages)
- Add rel="noopener noreferrer" to target=_blank links in generated rows
- HTML-escape fallback template content in renderHtml to prevent injection
- Move escapeHtml to module level so it's available before renderHtml body
- Neutralise dashboard.html template: placeholder title/h1/meta/stats/tbody
- Empty __md and filename in template (CLI populates at runtime)
- Add aria-label to search input and status/review selects

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* remove newline

* Regenerate docs/README.instructions.md

* refactor(pr-dashboard): move scripts/assets per skills spec, remove plugin

- Move pr-dashboard-cli.mjs and lib/utils.mjs into scripts/ per skills spec
- Move dashboard.html into assets/ per skills spec
- Update CLI template path and SKILL.md script path reference
- Remove plugins/pr-dashboard (redundant now that gh skills install works)
- Clean up marketplace.json and docs/README.plugins.md

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

skills/pr-dashboard/SKILL.md

@@ -0,0 +1,54 @@
+---
+name: pr-dashboard
+description: 'Open a GitHub PR dashboard in the browser. Use when the user asks to see their pull requests, open the PR dashboard, show PRs for a date range, or check PR status. Trigger phrases include "show my PRs", "open PR dashboard", "pull request dashboard".'
+---
+
+# PR Dashboard
+
+Generates and opens a GitHub PR dashboard in the browser for a given date range and role filter.
+
+**Prerequisites:** GitHub CLI (`gh`) must be installed and authenticated (`gh auth login`).
+
+## What to do
+
+Find the CLI script bundled with this skill and run it:
+
+```bash
+SKILL_SCRIPT=$(find ~/.copilot -name "pr-dashboard-cli.mjs" -path "*/pr-dashboard/scripts/*" 2>/dev/null | head -1)
+node "$SKILL_SCRIPT" "<query>" "<role>"
+```
+
+- `<query>`: the date range the user specified (default: `last 7 days`)
+- `<role>`: one of `Authored by me`, `Requested reviews`, `Assigned to me`, `All` (default: `Authored by me`)
+
+## Parsing the user's request
+
+Extract the date range and role from the user's message. Examples:
+
+| User says | query | role |
+|---|---|---|
+| show my PRs | `last 7 days` | `Authored by me` |
+| show my PRs last 2 weeks | `last 2 weeks` | `Authored by me` |
+| PR dashboard this month reviews | `this month` | `Requested reviews` |
+| PR dashboard march 2026 assigned | `march 2026` | `Assigned to me` |
+| show all PRs last 30 days | `last 30 days` | `All` |
+
+**Role keyword mapping:**
+- "my PRs", "authored", "I wrote" → `Authored by me`
+- "reviews", "review requested", "reviewing" → `Requested reviews`
+- "assigned" → `Assigned to me`
+- "all", "involves me" → `All`
+
+## Supported date range formats
+
+The script understands natural language — pass it through as-is:
+- `last 7 days`, `last 2 weeks`, `last 30 days`
+- `this week`, `last week`, `this month`, `last month`
+- `march 2026`, `feb 2025`
+- `2026-01-01 - 2026-03-31`
+- `2025` (whole year)
+
+## After running
+
+Tell the user the dashboard is opening in their browser. The script outputs progress to stdout. If it exits with an error, show the error output and suggest they run `gh auth login` if it's an auth issue.
+