feat(webui): Gitea issue and PR linkage console (Closes #645)

Add a Phase 3 read-only console that resolves issue↔PR linkage with
evidence (closes keyword, branch marker, body mention), surfaces the
latest canonical handoff for a focused thread, and deep-links to Gitea
only under the admin reveal opt-in.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

webui/queue_loader.py

@@ -211,6 +211,19 @@ def _pagination_from_pages(
     )
 
 
+_SUPPORTED_FETCH_STATES = ("open", "closed", "all")
+
+
+def _safe_state(state: str | None) -> str:
+    """Constrain a caller-supplied item state before it reaches a query string.
+
+    The value is interpolated into the Gitea URL, so an unrecognised state falls
+    back to ``open`` rather than being passed through.
+    """
+    text = (state or "open").strip().lower()
+    return text if text in _SUPPORTED_FETCH_STATES else "open"
+
+
 def _fetch_prs(
     host: str,
     org: str,
@@ -218,8 +231,15 @@ def _fetch_prs(
     auth: str,
     *,
     per_page: int = 50,
+    state: str = "open",
 ) -> tuple[list[dict], PaginationMeta]:
-    url = f"{repo_api_url(host, org, repo)}/pulls?state=open"
+    """Fetch PRs in *state* (``open``, ``closed``, or ``all``).
+
+    The queue dashboard only ever wants the open window, so ``open`` stays the
+    default. The linkage console (#645) widens it, because a landed issue↔PR
+    edge lives on a merged PR.
+    """
+    url = f"{repo_api_url(host, org, repo)}/pulls?state={_safe_state(state)}"
     all_raw: list[dict] = []
     pages_fetched = 0
     is_final = False
@@ -248,8 +268,13 @@ def _fetch_issues(
     auth: str,
     *,
     per_page: int = 50,
+    state: str = "open",
 ) -> tuple[list[dict], PaginationMeta]:
-    url = f"{repo_api_url(host, org, repo)}/issues?state=open&type=issues"
+    """Fetch issues in *state* (``open``, ``closed``, or ``all``); see :func:`_fetch_prs`."""
+    url = (
+        f"{repo_api_url(host, org, repo)}/issues"
+        f"?state={_safe_state(state)}&type=issues"
+    )
     all_raw: list[dict] = []
     page = 1
     pages_fetched = 0